---
_id: '13443'
abstract:
- lang: eng
  text: 'The ages of solar-like stars have been at the center of many studies such
    as exoplanet characterization or Galactic-archeology. While ages are usually computed
    from stellar evolution models, relations linking ages to other stellar properties,
    such as rotation and magnetic activity, have been investigated. With the large
    catalog of 55,232 rotation periods, Prot, and photometric magnetic activity index,
    Sph from Kepler data, we have the opportunity to look for such magneto-gyro-chronology
    relations. Stellar ages are obtained with two stellar evolution codes that include
    treatment of angular momentum evolution, hence using Prot as input in addition
    to classical atmospheric parameters. We explore two different ways of predicting
    stellar ages on three subsamples with spectroscopic observations: solar analogs,
    late-F and G dwarfs, and K dwarfs. We first perform a Bayesian analysis to derive
    relations between Sph and ages between 1 and 5 Gyr, and other stellar properties.
    For late-F and G dwarfs, and K dwarfs, the multivariate regression favors the
    model with Prot and Sph with median differences of 0.1% and 0.2%, respectively.
    We also apply Machine Learning techniques with a Random Forest algorithm to predict
    ages up to 14 Gyr with the same set of input parameters. For late-F, G and K dwarfs
    together, predicted ages are on average within 5.3% of the model ages and improve
    to 3.1% when including Prot. These are very promising results for a quick age
    estimation for solar-like stars with photometric observations, especially with
    current and future space missions.'
acknowledgement: 'This paper includes data collected by the Kepler mission and obtained
  from the MAST data archive at the Space Telescope Science Institute (STScI). Funding
  for the Kepler mission is provided by the NASA Science Mission Directorate. STScI
  is operated by the Association of Universities for Research in Astronomy, Inc.,
  under NASA contract NAS 5–26555. We acknowledge that this research was supported
  in part by the National Science Foundation under grant No. NSF PHY-1748958. S.M.
  acknowledges support from the Spanish Ministry of Science and Innovation (MICINN)
  with the Ramón y Cajal fellowship No. RYC-2015-17697, the grant No. PID2019-107061GB-C66,
  and through AEI under the Severo Ochoa Centres of Excellence Programme 2020–2023
  (CEX2019-000920-S). S.M. and D.G.R. acknowledge support from the Spanish Ministry
  of Science and Innovation (MICINN) with the grant No. PID2019-107187GB-I00. Z.R.C.
  acknowledges support from National Aeronautics and Space Administration via the
  TESS Guest Investigator Program (grant No. 80NSSC18K18584). The work presented here
  was partially supported by the NASA grant NNX17AF27G. A.R.G.S. acknowledges the
  support by FCT through national funds and by FEDER through COMPETE2020 by the following
  grants: UIDB/04434/2020 and UIDP/04434/2020. A.R.G.S. is supported by FCT through
  the work contract No. 2020.02480.CEECIND/CP1631/CT0001. R.A.G., L.A., and S.N.B.
  acknowledge the support from PLATO and GOLF CNES grants. S.N.B. acknowledges support
  from PLATO ASI-INAF agreement No. 2015-019-R.1-2018.'
article_number: '131'
article_processing_charge: Yes
article_type: original
author:
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Zachary R.
  full_name: Claytor, Zachary R.
  last_name: Claytor
- first_name: Ângela R. G.
  full_name: Santos, Ângela R. G.
  last_name: Santos
- first_name: Rafael A.
  full_name: García, Rafael A.
  last_name: García
- first_name: Louis
  full_name: Amard, Louis
  last_name: Amard
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Enrico
  full_name: Corsaro, Enrico
  last_name: Corsaro
- first_name: Alfio
  full_name: Bonanno, Alfio
  last_name: Bonanno
- first_name: Sylvain N.
  full_name: Breton, Sylvain N.
  last_name: Breton
- first_name: Diego
  full_name: Godoy-Rivera, Diego
  last_name: Godoy-Rivera
- first_name: Marc H.
  full_name: Pinsonneault, Marc H.
  last_name: Pinsonneault
- first_name: Jennifer
  full_name: van Saders, Jennifer
  last_name: van Saders
citation:
  ama: Mathur S, Claytor ZR, Santos ÂRG, et al. Magnetic activity evolution of solar-like
    stars. I. Sph–age relation derived from Kepler observations. <i>The Astrophysical
    Journal</i>. 2023;952(2). doi:<a href="https://doi.org/10.3847/1538-4357/acd118">10.3847/1538-4357/acd118</a>
  apa: Mathur, S., Claytor, Z. R., Santos, Â. R. G., García, R. A., Amard, L., Bugnet,
    L. A., … van Saders, J. (2023). Magnetic activity evolution of solar-like stars.
    I. Sph–age relation derived from Kepler observations. <i>The Astrophysical Journal</i>.
    American Astronomical Society. <a href="https://doi.org/10.3847/1538-4357/acd118">https://doi.org/10.3847/1538-4357/acd118</a>
  chicago: Mathur, Savita, Zachary R. Claytor, Ângela R. G. Santos, Rafael A. García,
    Louis Amard, Lisa Annabelle Bugnet, Enrico Corsaro, et al. “Magnetic Activity
    Evolution of Solar-like Stars. I. Sph–Age Relation Derived from Kepler Observations.”
    <i>The Astrophysical Journal</i>. American Astronomical Society, 2023. <a href="https://doi.org/10.3847/1538-4357/acd118">https://doi.org/10.3847/1538-4357/acd118</a>.
  ieee: S. Mathur <i>et al.</i>, “Magnetic activity evolution of solar-like stars.
    I. Sph–age relation derived from Kepler observations,” <i>The Astrophysical Journal</i>,
    vol. 952, no. 2. American Astronomical Society, 2023.
  ista: Mathur S, Claytor ZR, Santos ÂRG, García RA, Amard L, Bugnet LA, Corsaro E,
    Bonanno A, Breton SN, Godoy-Rivera D, Pinsonneault MH, van Saders J. 2023. Magnetic
    activity evolution of solar-like stars. I. Sph–age relation derived from Kepler
    observations. The Astrophysical Journal. 952(2), 131.
  mla: Mathur, Savita, et al. “Magnetic Activity Evolution of Solar-like Stars. I.
    Sph–Age Relation Derived from Kepler Observations.” <i>The Astrophysical Journal</i>,
    vol. 952, no. 2, 131, American Astronomical Society, 2023, doi:<a href="https://doi.org/10.3847/1538-4357/acd118">10.3847/1538-4357/acd118</a>.
  short: S. Mathur, Z.R. Claytor, Â.R.G. Santos, R.A. García, L. Amard, L.A. Bugnet,
    E. Corsaro, A. Bonanno, S.N. Breton, D. Godoy-Rivera, M.H. Pinsonneault, J. van
    Saders, The Astrophysical Journal 952 (2023).
date_created: 2023-08-01T14:19:16Z
date_published: 2023-08-01T00:00:00Z
date_updated: 2023-12-13T12:00:15Z
day: '01'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.3847/1538-4357/acd118
external_id:
  isi:
  - '001034185700001'
file:
- access_level: open_access
  checksum: f12452834d7ed6748dbf5ace18af4723
  content_type: application/pdf
  creator: dernst
  date_created: 2023-08-02T07:42:26Z
  date_updated: 2023-08-02T07:42:26Z
  file_id: '13448'
  file_name: 2023_AstrophysicalJour_Mathur.pdf
  file_size: 4192386
  relation: main_file
  success: 1
file_date_updated: 2023-08-02T07:42:26Z
has_accepted_license: '1'
intvolume: '       952'
isi: 1
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
publication: The Astrophysical Journal
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: American Astronomical Society
quality_controlled: '1'
status: public
title: Magnetic activity evolution of solar-like stars. I. Sph–age relation derived
  from Kepler observations
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 952
year: '2023'
...
---
_id: '13447'
abstract:
- lang: eng
  text: Asteroseismology has transformed stellar astrophysics. Red giant asteroseismology
    is a prime example, with oscillation periods and amplitudes that are readily detectable
    with time-domain space-based telescopes. These oscillations can be used to infer
    masses, ages and radii for large numbers of stars, providing unique constraints
    on stellar populations in our galaxy. The cadence, duration, and spatial resolution
    of the Roman galactic bulge time-domain survey (GBTDS) are well-suited for asteroseismology
    and will probe an important population not studied by prior missions. We identify
    photometric precision as a key requirement for realizing the potential of asteroseismology
    with Roman. A precision of 1 mmag per 15-min cadence or better for saturated stars
    will enable detections of the populous red clump star population in the Galactic
    bulge. If the survey efficiency is better than expected, we argue for repeat observations
    of the same fields to improve photometric precision, or covering additional fields
    to expand the stellar population reach if the photometric precision for saturated
    stars is better than 1 mmag. Asteroseismology is relatively insensitive to the
    timing of the observations during the mission, and the prime red clump targets
    can be observed in a single 70 day campaign in any given field. Complementary
    stellar characterization, particularly astrometry tied to the Gaia system, will
    also dramatically expand the diagnostic power of asteroseismology. We also highlight
    synergies to Roman GBTDS exoplanet science using transits and microlensing.
article_number: '2307.03237'
article_processing_charge: No
arxiv: 1
author:
- first_name: Daniel
  full_name: Huber, Daniel
  last_name: Huber
- first_name: Marc
  full_name: Pinsonneault, Marc
  last_name: Pinsonneault
- first_name: Paul
  full_name: Beck, Paul
  last_name: Beck
- first_name: Timothy R.
  full_name: Bedding, Timothy R.
  last_name: Bedding
- first_name: Joss Bland-Hawthorn
  full_name: Joss Bland-Hawthorn, Joss Bland-Hawthorn
  last_name: Joss Bland-Hawthorn
- first_name: Sylvain N.
  full_name: Breton, Sylvain N.
  last_name: Breton
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: William J.
  full_name: Chaplin, William J.
  last_name: Chaplin
- first_name: Rafael A.
  full_name: Garcia, Rafael A.
  last_name: Garcia
- first_name: Samuel K.
  full_name: Grunblatt, Samuel K.
  last_name: Grunblatt
- first_name: Joyce A.
  full_name: Guzik, Joyce A.
  last_name: Guzik
- first_name: Saskia
  full_name: Hekker, Saskia
  last_name: Hekker
- first_name: Steven D.
  full_name: Kawaler, Steven D.
  last_name: Kawaler
- first_name: Stephane
  full_name: Mathis, Stephane
  last_name: Mathis
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Travis
  full_name: Metcalfe, Travis
  last_name: Metcalfe
- first_name: Benoit
  full_name: Mosser, Benoit
  last_name: Mosser
- first_name: Melissa K.
  full_name: Ness, Melissa K.
  last_name: Ness
- first_name: Anthony L.
  full_name: Piro, Anthony L.
  last_name: Piro
- first_name: Aldo
  full_name: Serenelli, Aldo
  last_name: Serenelli
- first_name: Sanjib
  full_name: Sharma, Sanjib
  last_name: Sharma
- first_name: David R.
  full_name: Soderblom, David R.
  last_name: Soderblom
- first_name: Keivan G.
  full_name: Stassun, Keivan G.
  last_name: Stassun
- first_name: Dennis
  full_name: Stello, Dennis
  last_name: Stello
- first_name: Jamie
  full_name: Tayar, Jamie
  last_name: Tayar
- first_name: Gerard T. van
  full_name: Belle, Gerard T. van
  last_name: Belle
- first_name: Joel C.
  full_name: Zinn, Joel C.
  last_name: Zinn
citation:
  ama: Huber D, Pinsonneault M, Beck P, et al. Asteroseismology with the Roman galactic
    bulge time-domain survey. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2307.03237">10.48550/arXiv.2307.03237</a>
  apa: Huber, D., Pinsonneault, M., Beck, P., Bedding, T. R., Joss Bland-Hawthorn,
    J. B.-H., Breton, S. N., … Zinn, J. C. (n.d.). Asteroseismology with the Roman
    galactic bulge time-domain survey. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2307.03237">https://doi.org/10.48550/arXiv.2307.03237</a>
  chicago: Huber, Daniel, Marc Pinsonneault, Paul Beck, Timothy R. Bedding, Joss Bland-Hawthorn
    Joss Bland-Hawthorn, Sylvain N. Breton, Lisa Annabelle Bugnet, et al. “Asteroseismology
    with the Roman Galactic Bulge Time-Domain Survey.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.2307.03237">https://doi.org/10.48550/arXiv.2307.03237</a>.
  ieee: D. Huber <i>et al.</i>, “Asteroseismology with the Roman galactic bulge time-domain
    survey,” <i>arXiv</i>. .
  ista: Huber D, Pinsonneault M, Beck P, Bedding TR, Joss Bland-Hawthorn JB-H, Breton
    SN, Bugnet LA, Chaplin WJ, Garcia RA, Grunblatt SK, Guzik JA, Hekker S, Kawaler
    SD, Mathis S, Mathur S, Metcalfe T, Mosser B, Ness MK, Piro AL, Serenelli A, Sharma
    S, Soderblom DR, Stassun KG, Stello D, Tayar J, Belle GT van, Zinn JC. Asteroseismology
    with the Roman galactic bulge time-domain survey. arXiv, 2307.03237.
  mla: Huber, Daniel, et al. “Asteroseismology with the Roman Galactic Bulge Time-Domain
    Survey.” <i>ArXiv</i>, 2307.03237, doi:<a href="https://doi.org/10.48550/arXiv.2307.03237">10.48550/arXiv.2307.03237</a>.
  short: D. Huber, M. Pinsonneault, P. Beck, T.R. Bedding, J.B.-H. Joss Bland-Hawthorn,
    S.N. Breton, L.A. Bugnet, W.J. Chaplin, R.A. Garcia, S.K. Grunblatt, J.A. Guzik,
    S. Hekker, S.D. Kawaler, S. Mathis, S. Mathur, T. Metcalfe, B. Mosser, M.K. Ness,
    A.L. Piro, A. Serenelli, S. Sharma, D.R. Soderblom, K.G. Stassun, D. Stello, J.
    Tayar, G.T. van Belle, J.C. Zinn, ArXiv (n.d.).
date_created: 2023-08-02T07:30:43Z
date_published: 2023-07-06T00:00:00Z
date_updated: 2023-08-02T07:36:00Z
day: '06'
department:
- _id: LiBu
doi: 10.48550/arXiv.2307.03237
external_id:
  arxiv:
  - '2307.03237'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2307.03237
month: '07'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: submitted
status: public
title: Asteroseismology with the Roman galactic bulge time-domain survey
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...
---
_id: '14256'
abstract:
- lang: eng
  text: "Context. Space asteroseismology is revolutionizing our knowledge of the internal
    structure and dynamics of stars. A breakthrough is ongoing with the recent discoveries
    of signatures of strong magnetic fields in the core of red giant stars. The key
    signature for such a detection is the asymmetry these fields induce in the frequency
    splittings of observed dipolar mixed gravito-acoustic modes.\r\nAims. We investigate
    the ability of the observed asymmetries of the frequency splittings of dipolar
    mixed modes to constrain the geometrical properties of deep magnetic fields.\r\nMethods.
    We used the powerful analytical Racah-Wigner algebra used in quantum mechanics
    to characterize the geometrical couplings of dipolar mixed oscillation modes with
    various realistically plausible topologies of fossil magnetic fields. We also
    computed the induced perturbation of their frequencies.\r\nResults. First, in
    the case of an oblique magnetic dipole, we provide the exact analytical expression
    of the asymmetry as a function of the angle between the rotation and magnetic
    axes. Its value provides a direct measure of this angle. Second, considering a
    combination of axisymmetric dipolar and quadrupolar fields, we show how the asymmetry
    is blind to the unraveling of the relative strength and sign of each component.
    Finally, in the case of a given multipole, we show that a negative asymmetry is
    a signature of non-axisymmetric topologies.\r\nConclusions. Asymmetries of dipolar
    mixed modes provide a key bit of information on the geometrical topology of deep
    fossil magnetic fields, but this is insufficient on its own. Asteroseismic constraints
    should therefore be combined with spectropolarimetric observations and numerical
    simulations, which aim to predict the more probable stable large-scale geometries."
acknowledgement: The authors are grateful to the referee for her/his detailed and
  constructive report, which has allowed us to improve our article. S. M. acknowledges
  support from the CNES GOLF-SOHO and PLATO grants at CEA/DAp and PNPS (CNRS/INSU).
  We thank R. A. Garcia for fruitful discussions and suggestions.
article_number: L9
article_processing_charge: Yes (in subscription journal)
article_type: letter_note
arxiv: 1
author:
- first_name: S.
  full_name: Mathis, S.
  last_name: Mathis
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
citation:
  ama: 'Mathis S, Bugnet LA. Asymmetries of frequency splittings of dipolar mixed
    modes: A window on the topology of deep magnetic fields. <i>Astronomy and Astrophysics</i>.
    2023;676. doi:<a href="https://doi.org/10.1051/0004-6361/202346832">10.1051/0004-6361/202346832</a>'
  apa: 'Mathis, S., &#38; Bugnet, L. A. (2023). Asymmetries of frequency splittings
    of dipolar mixed modes: A window on the topology of deep magnetic fields. <i>Astronomy
    and Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202346832">https://doi.org/10.1051/0004-6361/202346832</a>'
  chicago: 'Mathis, S., and Lisa Annabelle Bugnet. “Asymmetries of Frequency Splittings
    of Dipolar Mixed Modes: A Window on the Topology of Deep Magnetic Fields.” <i>Astronomy
    and Astrophysics</i>. EDP Sciences, 2023. <a href="https://doi.org/10.1051/0004-6361/202346832">https://doi.org/10.1051/0004-6361/202346832</a>.'
  ieee: 'S. Mathis and L. A. Bugnet, “Asymmetries of frequency splittings of dipolar
    mixed modes: A window on the topology of deep magnetic fields,” <i>Astronomy and
    Astrophysics</i>, vol. 676. EDP Sciences, 2023.'
  ista: 'Mathis S, Bugnet LA. 2023. Asymmetries of frequency splittings of dipolar
    mixed modes: A window on the topology of deep magnetic fields. Astronomy and Astrophysics.
    676, L9.'
  mla: 'Mathis, S., and Lisa Annabelle Bugnet. “Asymmetries of Frequency Splittings
    of Dipolar Mixed Modes: A Window on the Topology of Deep Magnetic Fields.” <i>Astronomy
    and Astrophysics</i>, vol. 676, L9, EDP Sciences, 2023, doi:<a href="https://doi.org/10.1051/0004-6361/202346832">10.1051/0004-6361/202346832</a>.'
  short: S. Mathis, L.A. Bugnet, Astronomy and Astrophysics 676 (2023).
date_created: 2023-09-03T22:01:15Z
date_published: 2023-08-01T00:00:00Z
date_updated: 2023-09-06T11:05:58Z
day: '01'
ddc:
- '520'
department:
- _id: LiBu
doi: 10.1051/0004-6361/202346832
external_id:
  arxiv:
  - '2306.11587'
  isi:
  - '001046037700007'
file:
- access_level: open_access
  checksum: 7b30d26fb2b7bcb5b5be1414950615f9
  content_type: application/pdf
  creator: dernst
  date_created: 2023-09-06T07:13:19Z
  date_updated: 2023-09-06T07:13:19Z
  file_id: '14271'
  file_name: 2023_AstronomyAstrophysics_Mathis.pdf
  file_size: 458120
  relation: main_file
  success: 1
file_date_updated: 2023-09-06T07:13:19Z
has_accepted_license: '1'
intvolume: '       676'
isi: 1
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
publication: Astronomy and Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Asymmetries of frequency splittings of dipolar mixed modes: A window on the
  topology of deep magnetic fields'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 676
year: '2023'
...
---
_id: '11600'
abstract:
- lang: eng
  text: The Sun’s surface hosts varying magnetic activities and rotation rates (from
    equator to pole), and unique solar weather. Now, a combination of ground and space
    observations has unveiled a previously undetected magnetized plasma current.
article_processing_charge: No
article_type: letter_note
author:
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
citation:
  ama: Bugnet LA. Hidden currents at the Sun’s surface. <i>Nature Astronomy</i>. 2022;6:631-632.
    doi:<a href="https://doi.org/10.1038/s41550-022-01683-2">10.1038/s41550-022-01683-2</a>
  apa: Bugnet, L. A. (2022). Hidden currents at the Sun’s surface. <i>Nature Astronomy</i>.
    Springer Nature. <a href="https://doi.org/10.1038/s41550-022-01683-2">https://doi.org/10.1038/s41550-022-01683-2</a>
  chicago: Bugnet, Lisa Annabelle. “Hidden Currents at the Sun’s Surface.” <i>Nature
    Astronomy</i>. Springer Nature, 2022. <a href="https://doi.org/10.1038/s41550-022-01683-2">https://doi.org/10.1038/s41550-022-01683-2</a>.
  ieee: L. A. Bugnet, “Hidden currents at the Sun’s surface,” <i>Nature Astronomy</i>,
    vol. 6. Springer Nature, pp. 631–632, 2022.
  ista: Bugnet LA. 2022. Hidden currents at the Sun’s surface. Nature Astronomy. 6,
    631–632.
  mla: Bugnet, Lisa Annabelle. “Hidden Currents at the Sun’s Surface.” <i>Nature Astronomy</i>,
    vol. 6, Springer Nature, 2022, pp. 631–32, doi:<a href="https://doi.org/10.1038/s41550-022-01683-2">10.1038/s41550-022-01683-2</a>.
  short: L.A. Bugnet, Nature Astronomy 6 (2022) 631–632.
date_created: 2022-07-18T09:34:37Z
date_published: 2022-05-18T00:00:00Z
date_updated: 2022-08-19T09:52:21Z
day: '18'
doi: 10.1038/s41550-022-01683-2
extern: '1'
intvolume: '         6'
keyword:
- Astronomy and Astrophysics
language:
- iso: eng
month: '05'
oa_version: None
page: 631-632
publication: Nature Astronomy
publication_identifier:
  eissn:
  - 2397-3366
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Hidden currents at the Sun’s surface
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 6
year: '2022'
...
---
_id: '11601'
abstract:
- lang: eng
  text: We present the third and final data release of the K2 Galactic Archaeology
    Program (K2 GAP) for Campaigns C1–C8 and C10–C18. We provide asteroseismic radius
    and mass coefficients, κR and κM, for ∼19,000 red giant stars, which translate
    directly to radius and mass given a temperature. As such, K2 GAP DR3 represents
    the largest asteroseismic sample in the literature to date. K2 GAP DR3 stellar
    parameters are calibrated to be on an absolute parallactic scale based on Gaia
    DR2, with red giant branch and red clump evolutionary state classifications provided
    via a machine-learning approach. Combining these stellar parameters with GALAH
    DR3 spectroscopy, we determine asteroseismic ages with precisions of ∼20%–30%
    and compare age-abundance relations to Galactic chemical evolution models among
    both low- and high-α populations for α, light, iron-peak, and neutron-capture
    elements. We confirm recent indications in the literature of both increased Ba
    production at late Galactic times as well as significant contributions to r-process
    enrichment from prompt sources associated with, e.g., core-collapse supernovae.
    With an eye toward other Galactic archeology applications, we characterize K2
    GAP DR3 uncertainties and completeness using injection tests, suggesting that
    K2 GAP DR3 is largely unbiased in mass/age, with uncertainties of 2.9% (stat.)
    ± 0.1% (syst.) and 6.7% (stat.) ± 0.3% (syst.) in κR and κM for red giant branch
    stars and 4.7% (stat.) ± 0.3% (syst.) and 11% (stat.) ± 0.9% (syst.) for red clump
    stars. We also identify percent-level asteroseismic systematics, which are likely
    related to the time baseline of the underlying data, and which therefore should
    be considered in TESS asteroseismic analysis.
acknowledgement: "We would like to thank the anonymous referee whose comments significantly
  improved the manuscript. J.C.Z. is supported by an NSF Astronomy and Astrophysics
  Postdoctoral Fellowship under award AST-2001869. J.C.Z. and M.H.P. acknowledge support
  from NASA grants 80NSSC18K0391 and NNX17AJ40G. Y.E. and C.J. acknowledge the support
  of the UK Science and Technology Facilities Council (STFC). S.M. acknowledges support
  from the Spanish Ministry of Science and Innovation with the Ramon y Cajal fellowship
  number RYC-2015-17697 and the grant number PID2019-107187GB-I00. R.A.G. acknowledges
  funding received from the PLATO CNES grant. C.K. acknowledges funding from the UK
  Science and Technology Facilities Council (STFC) through grants ST/M000958/1, ST/R000905/1,
  and ST/V000632/1.\r\n\r\nFunding for the Stellar Astrophysics Centre (SAC) is provided
  by the Danish National Research Foundation (grant agreement No. DNRF106).\r\n\r\nThe
  K2 Galactic Archaeology Program is supported by the National Aeronautics and Space
  Administration under grant NNX16AJ17G issued through the K2 Guest Observer Program.
  This publication makes use of data products from the Two Micron All Sky Survey,
  which is a joint project of the University of Massachusetts and the Infrared Processing
  and Analysis Center/California Institute of Technology, funded by the National Aeronautics
  and Space Administration and the National Science Foundation.\r\n\r\nThis paper
  includes data collected by the Kepler mission. Funding for the Kepler mission is
  provided by the NASA Science Mission directorate.\r\n\r\nParts of this research
  were supported by the Australian Research Council Centre of Excellence for All Sky
  Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013.\r\n\r\nThis
  research was partially conducted during the Exostar19 program at the Kavli Institute
  for Theoretical Physics at UC Santa Barbara, which was supported in part by the
  National Science Foundation under grant No. NSF PHY-1748958.\r\n\r\nBased in part
  on data obtained at Siding Spring Observatory via GALAH. We acknowledge the traditional
  owners of the land on which the AAT stands, the Gamilaraay people, and pay our respects
  to elders past and present.\r\n\r\nThis work has made use of data from the European
  Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by
  the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).
  Funding for DPAC has been provided by national institutions, in particular the institutions
  participating in the Gaia Multilateral Agreement.\r\n\r\nFunding for the Sloan Digital
  Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department
  of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges
  support and resources from the Center for High-Performance Computing at the University
  of Utah (www.sdss.org).\r\n\r\nSoftware: asfgrid (Sharma & Stello 2016), corner
  (Foreman-Mackey 2016), emcee (Foreman-Mackey et al. 2013), NumPy (Walt 2011), pandas
  (McKinney 2010), Matplotlib (Hunter 2007), IPython (Pérez & Granger 2007), SciPy
  (Virtanen et al.2020)."
article_number: '191'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Joel C.
  full_name: Zinn, Joel C.
  last_name: Zinn
- first_name: Dennis
  full_name: Stello, Dennis
  last_name: Stello
- first_name: Yvonne
  full_name: Elsworth, Yvonne
  last_name: Elsworth
- first_name: Rafael A.
  full_name: García, Rafael A.
  last_name: García
- first_name: Thomas
  full_name: Kallinger, Thomas
  last_name: Kallinger
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Benoît
  full_name: Mosser, Benoît
  last_name: Mosser
- first_name: Marc
  full_name: Hon, Marc
  last_name: Hon
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Caitlin
  full_name: Jones, Caitlin
  last_name: Jones
- first_name: Claudia
  full_name: Reyes, Claudia
  last_name: Reyes
- first_name: Sanjib
  full_name: Sharma, Sanjib
  last_name: Sharma
- first_name: Ralph
  full_name: Schönrich, Ralph
  last_name: Schönrich
- first_name: Jack T.
  full_name: Warfield, Jack T.
  last_name: Warfield
- first_name: Rodrigo
  full_name: Luger, Rodrigo
  last_name: Luger
- first_name: Andrew
  full_name: Vanderburg, Andrew
  last_name: Vanderburg
- first_name: Chiaki
  full_name: Kobayashi, Chiaki
  last_name: Kobayashi
- first_name: Marc H.
  full_name: Pinsonneault, Marc H.
  last_name: Pinsonneault
- first_name: Jennifer A.
  full_name: Johnson, Jennifer A.
  last_name: Johnson
- first_name: Daniel
  full_name: Huber, Daniel
  last_name: Huber
- first_name: Sven
  full_name: Buder, Sven
  last_name: Buder
- first_name: Meridith
  full_name: Joyce, Meridith
  last_name: Joyce
- first_name: Joss
  full_name: Bland-Hawthorn, Joss
  last_name: Bland-Hawthorn
- first_name: Luca
  full_name: Casagrande, Luca
  last_name: Casagrande
- first_name: Geraint F.
  full_name: Lewis, Geraint F.
  last_name: Lewis
- first_name: Andrea
  full_name: Miglio, Andrea
  last_name: Miglio
- first_name: Thomas
  full_name: Nordlander, Thomas
  last_name: Nordlander
- first_name: Guy R.
  full_name: Davies, Guy R.
  last_name: Davies
- first_name: Gayandhi De
  full_name: Silva, Gayandhi De
  last_name: Silva
- first_name: William J.
  full_name: Chaplin, William J.
  last_name: Chaplin
- first_name: Victor
  full_name: Silva Aguirre, Victor
  last_name: Silva Aguirre
citation:
  ama: 'Zinn JC, Stello D, Elsworth Y, et al. The K2 Galactic Archaeology Program
    data release 3: Age-abundance patterns in C1–C8 and C10–C18. <i>The Astrophysical
    Journal</i>. 2022;926(2). doi:<a href="https://doi.org/10.3847/1538-4357/ac2c83">10.3847/1538-4357/ac2c83</a>'
  apa: 'Zinn, J. C., Stello, D., Elsworth, Y., García, R. A., Kallinger, T., Mathur,
    S., … Silva Aguirre, V. (2022). The K2 Galactic Archaeology Program data release
    3: Age-abundance patterns in C1–C8 and C10–C18. <i>The Astrophysical Journal</i>.
    IOP Publishing. <a href="https://doi.org/10.3847/1538-4357/ac2c83">https://doi.org/10.3847/1538-4357/ac2c83</a>'
  chicago: 'Zinn, Joel C., Dennis Stello, Yvonne Elsworth, Rafael A. García, Thomas
    Kallinger, Savita Mathur, Benoît Mosser, et al. “The K2 Galactic Archaeology Program
    Data Release 3: Age-Abundance Patterns in C1–C8 and C10–C18.” <i>The Astrophysical
    Journal</i>. IOP Publishing, 2022. <a href="https://doi.org/10.3847/1538-4357/ac2c83">https://doi.org/10.3847/1538-4357/ac2c83</a>.'
  ieee: 'J. C. Zinn <i>et al.</i>, “The K2 Galactic Archaeology Program data release
    3: Age-abundance patterns in C1–C8 and C10–C18,” <i>The Astrophysical Journal</i>,
    vol. 926, no. 2. IOP Publishing, 2022.'
  ista: 'Zinn JC, Stello D, Elsworth Y, García RA, Kallinger T, Mathur S, Mosser B,
    Hon M, Bugnet LA, Jones C, Reyes C, Sharma S, Schönrich R, Warfield JT, Luger
    R, Vanderburg A, Kobayashi C, Pinsonneault MH, Johnson JA, Huber D, Buder S, Joyce
    M, Bland-Hawthorn J, Casagrande L, Lewis GF, Miglio A, Nordlander T, Davies GR,
    Silva GD, Chaplin WJ, Silva Aguirre V. 2022. The K2 Galactic Archaeology Program
    data release 3: Age-abundance patterns in C1–C8 and C10–C18. The Astrophysical
    Journal. 926(2), 191.'
  mla: 'Zinn, Joel C., et al. “The K2 Galactic Archaeology Program Data Release 3:
    Age-Abundance Patterns in C1–C8 and C10–C18.” <i>The Astrophysical Journal</i>,
    vol. 926, no. 2, 191, IOP Publishing, 2022, doi:<a href="https://doi.org/10.3847/1538-4357/ac2c83">10.3847/1538-4357/ac2c83</a>.'
  short: J.C. Zinn, D. Stello, Y. Elsworth, R.A. García, T. Kallinger, S. Mathur,
    B. Mosser, M. Hon, L.A. Bugnet, C. Jones, C. Reyes, S. Sharma, R. Schönrich, J.T.
    Warfield, R. Luger, A. Vanderburg, C. Kobayashi, M.H. Pinsonneault, J.A. Johnson,
    D. Huber, S. Buder, M. Joyce, J. Bland-Hawthorn, L. Casagrande, G.F. Lewis, A.
    Miglio, T. Nordlander, G.R. Davies, G.D. Silva, W.J. Chaplin, V. Silva Aguirre,
    The Astrophysical Journal 926 (2022).
date_created: 2022-07-18T10:57:30Z
date_published: 2022-02-24T00:00:00Z
date_updated: 2022-08-19T09:52:08Z
day: '24'
doi: 10.3847/1538-4357/ac2c83
extern: '1'
external_id:
  arxiv:
  - '2108.05455'
intvolume: '       926'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2108.05455
month: '02'
oa: 1
oa_version: Preprint
publication: The Astrophysical Journal
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'The K2 Galactic Archaeology Program data release 3: Age-abundance patterns
  in C1–C8 and C10–C18'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 926
year: '2022'
...
---
_id: '11602'
abstract:
- lang: eng
  text: During the survey phase of the Kepler mission, several thousand stars were
    observed in short cadence, allowing for the detection of solar-like oscillations
    in more than 500 main-sequence and subgiant stars. These detections showed the
    power of asteroseismology in determining fundamental stellar parameters. However,
    the Kepler Science Office discovered an issue in the calibration that affected
    half of the store of short-cadence data, leading to a new data release (DR25)
    with corrections on the light curves. In this work, we re-analyzed the one-month
    time series of the Kepler survey phase to search for solar-like oscillations that
    might have been missed when using the previous data release. We studied the seismic
    parameters of 99 stars, among which there are 46 targets with new reported solar-like
    oscillations, increasing, by around 8%, the known sample of solar-like stars with
    an asteroseismic analysis of the short-cadence data from this mission. The majority
    of these stars have mid- to high-resolution spectroscopy publicly available with
    the LAMOST and APOGEE surveys, respectively, as well as precise Gaia parallaxes.
    We computed the masses and radii using seismic scaling relations and we find that
    this new sample features massive stars (above 1.2 M⊙ and up to 2 M⊙) and subgiants.
    We determined the granulation parameters and amplitude of the modes, which agree
    with the scaling relations derived for dwarfs and subgiants. The stars studied
    here are slightly fainter than the previously known sample of main-sequence and
    subgiants with asteroseismic detections. We also studied the surface rotation
    and magnetic activity levels of those stars. Our sample of 99 stars has similar
    levels of activity compared to the previously known sample and is in the same
    range as the Sun between the minimum and maximum of its activity cycle. We find
    that for seven stars, a possible blend could be the reason for the non-detection
    with the early data release. Finally, we compared the radii obtained from the
    scaling relations with the Gaia ones and we find that the Gaia radii are overestimated
    by 4.4%, on average, compared to the seismic radii, with a scatter of 12.3% and
    a decreasing trend according to the evolutionary stage. In addition, for homogeneity
    purposes, we re-analyzed the DR25 of the main-sequence and subgiant stars with
    solar-like oscillations that were previously detected and, as a result, we provide
    the global seismic parameters for a total of 525 stars.
acknowledgement: 'This paper includes data collected by the Kepler mission. Funding
  for the Kepler mission is provided by the NASA Science Mission directorate. Some
  of the data presented in this paper were obtained from the Mikulski Archive for
  Space Telescopes (MAST). STScI is operated by the Association of Universities for
  Research in Astronomy, Inc., under NASA contract NAS5-26555. S. M. acknowledges
  support by the Spanish Ministry of Science and Innovation with the Ramon y Cajal
  fellowship number RYC-2015-17697 and the grant number PID2019-107187GB-I00. R. A.
  G. and S. N. B acknowledge the support from PLATO and GOLF CNES grants. A. R. G.
  S. acknowledges the support from National Aeronautics and Space Administration under
  Grant NNX17AF27G and STFC consolidated grant ST/T000252/1. D.H. acknowledges support
  from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration
  (80NSSC19K0597), and the National Science Foundation (AST-1717000). M.S. is supported
  by the Research Corporation for Science Advancement through Scialog award #26080.
  Guoshoujing Telescope (the Large Sky Area Multi-Object Fiber Spectroscopic Telescope
  LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciences.
  Funding for the project has been provided by the National Development and Reform
  Commission. LAMOST is operated and managed by the National Astronomical Observatories,
  Chinese Academy of Sciences.'
article_number: A31
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: S.
  full_name: Breton, S.
  last_name: Breton
- first_name: A. R. G.
  full_name: Santos, A. R. G.
  last_name: Santos
- first_name: B.
  full_name: Mosser, B.
  last_name: Mosser
- first_name: D.
  full_name: Huber, D.
  last_name: Huber
- first_name: M.
  full_name: Sayeed, M.
  last_name: Sayeed
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: A.
  full_name: Chontos, A.
  last_name: Chontos
citation:
  ama: Mathur S, García RA, Breton S, et al. Detections of solar-like oscillations
    in dwarfs and subgiants with Kepler DR25 short-cadence data. <i>Astronomy &#38;
    Astrophysics</i>. 2022;657. doi:<a href="https://doi.org/10.1051/0004-6361/202141168">10.1051/0004-6361/202141168</a>
  apa: Mathur, S., García, R. A., Breton, S., Santos, A. R. G., Mosser, B., Huber,
    D., … Chontos, A. (2022). Detections of solar-like oscillations in dwarfs and
    subgiants with Kepler DR25 short-cadence data. <i>Astronomy &#38; Astrophysics</i>.
    EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202141168">https://doi.org/10.1051/0004-6361/202141168</a>
  chicago: Mathur, S., R. A. García, S. Breton, A. R. G. Santos, B. Mosser, D. Huber,
    M. Sayeed, Lisa Annabelle Bugnet, and A. Chontos. “Detections of Solar-like Oscillations
    in Dwarfs and Subgiants with Kepler DR25 Short-Cadence Data.” <i>Astronomy &#38;
    Astrophysics</i>. EDP Sciences, 2022. <a href="https://doi.org/10.1051/0004-6361/202141168">https://doi.org/10.1051/0004-6361/202141168</a>.
  ieee: S. Mathur <i>et al.</i>, “Detections of solar-like oscillations in dwarfs
    and subgiants with Kepler DR25 short-cadence data,” <i>Astronomy &#38; Astrophysics</i>,
    vol. 657. EDP Sciences, 2022.
  ista: Mathur S, García RA, Breton S, Santos ARG, Mosser B, Huber D, Sayeed M, Bugnet
    LA, Chontos A. 2022. Detections of solar-like oscillations in dwarfs and subgiants
    with Kepler DR25 short-cadence data. Astronomy &#38; Astrophysics. 657, A31.
  mla: Mathur, S., et al. “Detections of Solar-like Oscillations in Dwarfs and Subgiants
    with Kepler DR25 Short-Cadence Data.” <i>Astronomy &#38; Astrophysics</i>, vol.
    657, A31, EDP Sciences, 2022, doi:<a href="https://doi.org/10.1051/0004-6361/202141168">10.1051/0004-6361/202141168</a>.
  short: S. Mathur, R.A. García, S. Breton, A.R.G. Santos, B. Mosser, D. Huber, M.
    Sayeed, L.A. Bugnet, A. Chontos, Astronomy &#38; Astrophysics 657 (2022).
date_created: 2022-07-18T11:41:59Z
date_published: 2022-01-01T00:00:00Z
date_updated: 2022-08-19T09:56:58Z
day: '01'
doi: 10.1051/0004-6361/202141168
extern: '1'
external_id:
  arxiv:
  - '2109.14058'
intvolume: '       657'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2109.14058
month: '01'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: Detections of solar-like oscillations in dwarfs and subgiants with Kepler DR25
  short-cadence data
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 657
year: '2022'
...
---
_id: '11621'
abstract:
- lang: eng
  text: "Context. Asteroseismology has revealed small core-to-surface rotation contrasts
    in stars in the whole Hertzsprung–Russell diagram. This is the signature of strong
    transport of angular momentum (AM) in stellar interiors. One of the plausible
    candidates to efficiently carry AM is magnetic fields with various topologies
    that could be present in stellar radiative zones. Among them, strong axisymmetric
    azimuthal (toroidal) magnetic fields have received a lot of interest. Indeed,
    if they are subject to the so-called Tayler instability, the accompanying triggered
    Maxwell stresses can transport AM efficiently. In addition, the electromotive
    force induced by the fluctuations of magnetic and velocity fields could potentially
    sustain a dynamo action that leads to the regeneration of the initial strong axisymmetric
    azimuthal magnetic field.\r\n\r\nAims. The key question we aim to answer is whether
    we can detect signatures of these deep strong azimuthal magnetic fields. The only
    way to answer this question is asteroseismology, and the best laboratories of
    study are intermediate-mass and massive stars with external radiative envelopes.
    Most of these are rapid rotators during their main sequence. Therefore, we have
    to study stellar pulsations propagating in stably stratified, rotating, and potentially
    strongly magnetised radiative zones, namely magneto-gravito-inertial (MGI) waves.\r\n\r\nMethods.
    We generalise the traditional approximation of rotation (TAR) by simultaneously
    taking general axisymmetric differential rotation and azimuthal magnetic fields
    into account. Both the Coriolis acceleration and the Lorentz force are therefore
    treated in a non-perturbative way. Using this new formalism, we derive the asymptotic
    properties of MGI waves and their period spacings.\r\n\r\nResults. We find that
    toroidal magnetic fields induce a shift in the period spacings of gravity (g)
    and Rossby (r) modes. An equatorial azimuthal magnetic field with an amplitude
    of the order of 105 G leads to signatures that are detectable in period spacings
    for high-radial-order g and r modes in γ Doradus (γ Dor) and slowly pulsating
    B (SPB) stars. More complex hemispheric configurations are more difficult to observe,
    particularly when they are localised out of the propagation region of MGI modes,
    which can be localised in an equatorial belt.\r\n\r\nConclusions. The magnetic
    TAR, which takes into account toroidal magnetic fields in a non-perturbative way,
    is derived. This new formalism allows us to assess the effects of the magnetic
    field in γ Dor and SPB stars on g and r modes. We find that these effects should
    be detectable for equatorial fields thanks to modern space photometry using observations
    from Kepler, TESS CVZ, and PLATO."
acknowledgement: 'We thank the referee for her/his positive and constructive report,
  which has allowed us to improve the quality of our article. H.D. and S.M. acknowledge
  support from the CNES PLATO grant at CEA/DAp. T.V.R. gratefully acknowledges support
  from the Research Foundation Flanders (FWO) under grant agreement No. 12ZB620N and
  V414021N. This research was supported in part by the National Science Foundation
  under Grant No. NSF PHY-1748958. C.A. is supported by the KU Leuven Research Council
  (grant C16/18/005: PARADISE) as well as from the BELgian federal Science Policy
  Office (BELSPO) through a PLATO PRODEX grant.'
article_number: A133
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: H.
  full_name: Dhouib, H.
  last_name: Dhouib
- first_name: S.
  full_name: Mathis, S.
  last_name: Mathis
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: T.
  full_name: Van Reeth, T.
  last_name: Van Reeth
- first_name: C.
  full_name: Aerts, C.
  last_name: Aerts
citation:
  ama: 'Dhouib H, Mathis S, Bugnet LA, Van Reeth T, Aerts C. Detecting deep axisymmetric
    toroidal magnetic fields in stars: The traditional approximation of rotation for
    differentially rotating deep spherical shells with a general azimuthal magnetic
    field. <i>Astronomy &#38; Astrophysics</i>. 2022;661. doi:<a href="https://doi.org/10.1051/0004-6361/202142956">10.1051/0004-6361/202142956</a>'
  apa: 'Dhouib, H., Mathis, S., Bugnet, L. A., Van Reeth, T., &#38; Aerts, C. (2022).
    Detecting deep axisymmetric toroidal magnetic fields in stars: The traditional
    approximation of rotation for differentially rotating deep spherical shells with
    a general azimuthal magnetic field. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences.
    <a href="https://doi.org/10.1051/0004-6361/202142956">https://doi.org/10.1051/0004-6361/202142956</a>'
  chicago: 'Dhouib, H., S. Mathis, Lisa Annabelle Bugnet, T. Van Reeth, and C. Aerts.
    “Detecting Deep Axisymmetric Toroidal Magnetic Fields in Stars: The Traditional
    Approximation of Rotation for Differentially Rotating Deep Spherical Shells with
    a General Azimuthal Magnetic Field.” <i>Astronomy &#38; Astrophysics</i>. EDP
    Sciences, 2022. <a href="https://doi.org/10.1051/0004-6361/202142956">https://doi.org/10.1051/0004-6361/202142956</a>.'
  ieee: 'H. Dhouib, S. Mathis, L. A. Bugnet, T. Van Reeth, and C. Aerts, “Detecting
    deep axisymmetric toroidal magnetic fields in stars: The traditional approximation
    of rotation for differentially rotating deep spherical shells with a general azimuthal
    magnetic field,” <i>Astronomy &#38; Astrophysics</i>, vol. 661. EDP Sciences,
    2022.'
  ista: 'Dhouib H, Mathis S, Bugnet LA, Van Reeth T, Aerts C. 2022. Detecting deep
    axisymmetric toroidal magnetic fields in stars: The traditional approximation
    of rotation for differentially rotating deep spherical shells with a general azimuthal
    magnetic field. Astronomy &#38; Astrophysics. 661, A133.'
  mla: 'Dhouib, H., et al. “Detecting Deep Axisymmetric Toroidal Magnetic Fields in
    Stars: The Traditional Approximation of Rotation for Differentially Rotating Deep
    Spherical Shells with a General Azimuthal Magnetic Field.” <i>Astronomy &#38;
    Astrophysics</i>, vol. 661, A133, EDP Sciences, 2022, doi:<a href="https://doi.org/10.1051/0004-6361/202142956">10.1051/0004-6361/202142956</a>.'
  short: H. Dhouib, S. Mathis, L.A. Bugnet, T. Van Reeth, C. Aerts, Astronomy &#38;
    Astrophysics 661 (2022).
date_created: 2022-07-19T08:04:15Z
date_published: 2022-05-19T00:00:00Z
date_updated: 2022-08-22T07:58:54Z
day: '19'
doi: 10.1051/0004-6361/202142956
extern: '1'
external_id:
  arxiv:
  - '2202.10026'
intvolume: '       661'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- magnetohydrodynamics (MHD) / waves / stars
- 'rotation / stars: magnetic field / stars'
- oscillations / methods
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2202.10026
month: '05'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Detecting deep axisymmetric toroidal magnetic fields in stars: The traditional
  approximation of rotation for differentially rotating deep spherical shells with
  a general azimuthal magnetic field'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 661
year: '2022'
...
---
_id: '13445'
abstract:
- lang: eng
  text: Rotation is typically assumed to induce strictly symmetric rotational splitting
    into the rotational multiplets of pure p- and g-modes. However, for evolved stars
    exhibiting mixed modes, avoided crossings between different multiplet components
    are known to yield asymmetric rotational splitting, in particular for near-degenerate
    mixed-mode pairs, where notional pure p-modes are fortuitously in resonance with
    pure g-modes. These near-degeneracy effects have been described in subgiants,
    but their consequences for the characterization of internal rotation in red giants
    have not previously been investigated in detail, in part owing to theoretical
    intractability. We employ new developments in the analytic theory of mixed-mode
    coupling to study these near-resonance phenomena. In the vicinity of the most
    p-dominated mixed modes, the near-degenerate intrinsic asymmetry from pure rotational
    splitting increases dramatically over the course of stellar evolution, and it
    depends strongly on the mode-mixing fraction ζ. We also find that a linear treatment
    of rotation remains viable for describing the underlying p- and g-modes, even
    when it does not for the resulting mixed modes undergoing these avoided crossings.
    We explore observational consequences for potential measurements of asymmetric
    mixed-mode splitting, which has been proposed as a magnetic-field diagnostic.
    Finally, we propose improved measurement techniques for rotational characterization,
    exploiting the linearity of rotational effects on the underlying p/g-modes, while
    still accounting for these mixed-mode coupling effects.
article_number: '18'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: J. M. Joel
  full_name: Ong, J. M. Joel
  last_name: Ong
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Sarbani
  full_name: Basu, Sarbani
  last_name: Basu
citation:
  ama: Ong JMJ, Bugnet LA, Basu S. Mode mixing and rotational splittings. I. Near-degeneracy
    effects revisited. <i>The Astrophysical Journal</i>. 2022;940(1). doi:<a href="https://doi.org/10.3847/1538-4357/ac97e7">10.3847/1538-4357/ac97e7</a>
  apa: Ong, J. M. J., Bugnet, L. A., &#38; Basu, S. (2022). Mode mixing and rotational
    splittings. I. Near-degeneracy effects revisited. <i>The Astrophysical Journal</i>.
    American Astronomical Society. <a href="https://doi.org/10.3847/1538-4357/ac97e7">https://doi.org/10.3847/1538-4357/ac97e7</a>
  chicago: Ong, J. M. Joel, Lisa Annabelle Bugnet, and Sarbani Basu. “Mode Mixing
    and Rotational Splittings. I. Near-Degeneracy Effects Revisited.” <i>The Astrophysical
    Journal</i>. American Astronomical Society, 2022. <a href="https://doi.org/10.3847/1538-4357/ac97e7">https://doi.org/10.3847/1538-4357/ac97e7</a>.
  ieee: J. M. J. Ong, L. A. Bugnet, and S. Basu, “Mode mixing and rotational splittings.
    I. Near-degeneracy effects revisited,” <i>The Astrophysical Journal</i>, vol.
    940, no. 1. American Astronomical Society, 2022.
  ista: Ong JMJ, Bugnet LA, Basu S. 2022. Mode mixing and rotational splittings. I.
    Near-degeneracy effects revisited. The Astrophysical Journal. 940(1), 18.
  mla: Ong, J. M. Joel, et al. “Mode Mixing and Rotational Splittings. I. Near-Degeneracy
    Effects Revisited.” <i>The Astrophysical Journal</i>, vol. 940, no. 1, 18, American
    Astronomical Society, 2022, doi:<a href="https://doi.org/10.3847/1538-4357/ac97e7">10.3847/1538-4357/ac97e7</a>.
  short: J.M.J. Ong, L.A. Bugnet, S. Basu, The Astrophysical Journal 940 (2022).
date_created: 2023-08-01T14:20:41Z
date_published: 2022-11-16T00:00:00Z
date_updated: 2023-09-06T07:27:45Z
day: '16'
doi: 10.3847/1538-4357/ac97e7
extern: '1'
external_id:
  arxiv:
  - '2210.01928'
intvolume: '       940'
issue: '1'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2210.01928
month: '11'
oa: 1
oa_version: Published Version
publication: The Astrophysical Journal
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: American Astronomical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Mode mixing and rotational splittings. I. Near-degeneracy effects revisited
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 940
year: '2022'
...
---
_id: '11604'
abstract:
- lang: eng
  text: The NASA Transiting Exoplanet Survey Satellite (TESS) is observing tens of
    millions of stars with time spans ranging from ∼27 days to about 1 yr of continuous
    observations. This vast amount of data contains a wealth of information for variability,
    exoplanet, and stellar astrophysics studies but requires a number of processing
    steps before it can be fully utilized. In order to efficiently process all the
    TESS data and make it available to the wider scientific community, the TESS Data
    for Asteroseismology working group, as part of the TESS Asteroseismic Science
    Consortium, has created an automated open-source processing pipeline to produce
    light curves corrected for systematics from the short- and long-cadence raw photometry
    data and to classify these according to stellar variability type. We will process
    all stars down to a TESS magnitude of 15. This paper is the next in a series detailing
    how the pipeline works. Here, we present our methodology for the automatic variability
    classification of TESS photometry using an ensemble of supervised learners that
    are combined into a metaclassifier. We successfully validate our method using
    a carefully constructed labeled sample of Kepler Q9 light curves with a 27.4 days
    time span mimicking single-sector TESS observations, on which we obtain an overall
    accuracy of 94.9%. We demonstrate that our methodology can successfully classify
    stars outside of our labeled sample by applying it to all ∼167,000 stars observed
    in Q9 of the Kepler space mission.
acknowledgement: "The research leading to these results has received funding from
  the European Research Council (ERC) under the European Union's Horizon 2020 research
  and innovation program (grant agreement No. 670519: MAMSIE), from the KU Leuven
  Research Council (grant C16/18/005: PARADISE), from the Research Foundation Flanders
  (FWO) under grant agreement G0H5416N (ERC Runner Up Project), as well as from the
  BELgian federal Science Policy Office (BELSPO) through PRODEX grant PLATO. D.J.A
  acknowledges support from the STFC via an Ernest Rutherford Fellowship (ST/R00384X/1).
  Funding for the Stellar Astrophysics Centre is provided by The Danish National Research
  Foundation (grant agreement No.: DNRF106). R.H. and M.N.L. acknowledge the ESA PRODEX
  program. This research was supported by the National Aeronautics and Space Administration
  (80NSSC18K1585 and 80NSSC19K0379) awarded through the TESS Guest Investigator Program.
  K.J.B. is supported by the National Science Foundation under Award AST-1903828.
  J.S.K and K.J.B. were supported by funding from the European Research Council under
  the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement
  no. 338251 (StellarAges). D.M.B. gratefully acknowledges funding from a senior postdoctoral
  fellowship from the Research Foundation Flanders (FWO) with grant agreement No.
  1286521N. The research leading to these results has received funding from the Research
  Foundation Flanders (FWO) under grant agreement G0A2917N (BlackGEM). R.A.G. acknowledges
  support from the GOLF and PLATO CNES grants. L.M. was supported by the Premium Postdoctoral
  Research Program of the Hungarian Academy of Sciences. The research leading to these
  results has been supported by the Hungarian National Research, Development, and
  Innovation Office (NKFIH) grant KH_18 130405 and the Lendület LP2014-17 and LP2018-7/2020
  grants of the Hungarian Academy of Sciences. D.B. acknowledges support from the
  NASA TESS Guest Investigator Program under award 80NSSC19K0385.\r\n\r\nThis paper
  includes data collected by the TESS mission, which are publicly available from the
  Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided
  by NASA's Science Mission directorate. This research has made use of NASA's Astrophysics
  Data System as well as the NASA/IPAC Extragalactic Database (NED) which is operated
  by the Jet Propulsion Laboratory, California Institute of Technology, under contract
  with the National Aeronautics and Space Administration. Funding for the TESS Asteroseismic
  Science Operations Centre is provided by the Danish National Research Foundation
  (Grant agreement no.: DNRF106), ESA PRODEX (PEA 4000119301), and the Stellar Astrophysics
  Centre (SAC) at Aarhus University. We thank the TESS team and staff and TASC/TASOC
  for their support of the present work.\r\n\r\nThis paper includes data collected
  by the Kepler mission. Funding for the Kepler and K2 mission was provided by NASA's
  Science Mission Directorate. The authors acknowledge the efforts of the Kepler Mission
  team in obtaining the light-curve data and data validation products used in this
  publication. These data were generated by the Kepler Mission science pipeline through
  the efforts of the Kepler Science Operations Center and Science Office. The Kepler
  light curves are archived at the Mikulski Archive for Space Telescopes.\r\n\r\nThe
  numerical results presented in this work were obtained at the Centre for Scientific
  Computing, Aarhus. 37 This research made use of Astropy, a community-developed core
  Python package for Astronomy (Astropy Collaboration et al. 2013, 2018).\r\n\r\nSoftware:
  Scikit-learn (Pedregosa et al. 2011), Numpy (Harris et al. 2020), Astropy (Astropy
  Collaboration et al. 2013, 2018), Scipy (Virtanen et al. 2020), Pandas (McKinney
  2010; Pandas Development Team 2020), Lightkurve (Lightkurve Collaboration et al.
  2018), XGBoost (Chen & Guestrin 2016), Tensorflow (Abadi et al. 2015)."
article_number: '209'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: J.
  full_name: Audenaert, J.
  last_name: Audenaert
- first_name: J. S.
  full_name: Kuszlewicz, J. S.
  last_name: Kuszlewicz
- first_name: R.
  full_name: Handberg, R.
  last_name: Handberg
- first_name: A.
  full_name: Tkachenko, A.
  last_name: Tkachenko
- first_name: D. J.
  full_name: Armstrong, D. J.
  last_name: Armstrong
- first_name: M.
  full_name: Hon, M.
  last_name: Hon
- first_name: R.
  full_name: Kgoadi, R.
  last_name: Kgoadi
- first_name: M. N.
  full_name: Lund, M. N.
  last_name: Lund
- first_name: K. J.
  full_name: Bell, K. J.
  last_name: Bell
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: D. M.
  full_name: Bowman, D. M.
  last_name: Bowman
- first_name: C.
  full_name: Johnston, C.
  last_name: Johnston
- first_name: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: D.
  full_name: Stello, D.
  last_name: Stello
- first_name: L.
  full_name: Molnár, L.
  last_name: Molnár
- first_name: E.
  full_name: Plachy, E.
  last_name: Plachy
- first_name: D.
  full_name: Buzasi, D.
  last_name: Buzasi
- first_name: C.
  full_name: Aerts, C.
  last_name: Aerts
citation:
  ama: 'Audenaert J, Kuszlewicz JS, Handberg R, et al. TESS Data for Asteroseismology
    (T’DA) stellar variability classification pipeline: Setup and application to the
    Kepler Q9 data. <i>The Astronomical Journal</i>. 2021;162(5). doi:<a href="https://doi.org/10.3847/1538-3881/ac166a">10.3847/1538-3881/ac166a</a>'
  apa: 'Audenaert, J., Kuszlewicz, J. S., Handberg, R., Tkachenko, A., Armstrong,
    D. J., Hon, M., … Aerts, C. (2021). TESS Data for Asteroseismology (T’DA) stellar
    variability classification pipeline: Setup and application to the Kepler Q9 data.
    <i>The Astronomical Journal</i>. IOP Publishing. <a href="https://doi.org/10.3847/1538-3881/ac166a">https://doi.org/10.3847/1538-3881/ac166a</a>'
  chicago: 'Audenaert, J., J. S. Kuszlewicz, R. Handberg, A. Tkachenko, D. J. Armstrong,
    M. Hon, R. Kgoadi, et al. “TESS Data for Asteroseismology (T’DA) Stellar Variability
    Classification Pipeline: Setup and Application to the Kepler Q9 Data.” <i>The
    Astronomical Journal</i>. IOP Publishing, 2021. <a href="https://doi.org/10.3847/1538-3881/ac166a">https://doi.org/10.3847/1538-3881/ac166a</a>.'
  ieee: 'J. Audenaert <i>et al.</i>, “TESS Data for Asteroseismology (T’DA) stellar
    variability classification pipeline: Setup and application to the Kepler Q9 data,”
    <i>The Astronomical Journal</i>, vol. 162, no. 5. IOP Publishing, 2021.'
  ista: 'Audenaert J, Kuszlewicz JS, Handberg R, Tkachenko A, Armstrong DJ, Hon M,
    Kgoadi R, Lund MN, Bell KJ, Bugnet LA, Bowman DM, Johnston C, García RA, Stello
    D, Molnár L, Plachy E, Buzasi D, Aerts C. 2021. TESS Data for Asteroseismology
    (T’DA) stellar variability classification pipeline: Setup and application to the
    Kepler Q9 data. The Astronomical Journal. 162(5), 209.'
  mla: 'Audenaert, J., et al. “TESS Data for Asteroseismology (T’DA) Stellar Variability
    Classification Pipeline: Setup and Application to the Kepler Q9 Data.” <i>The
    Astronomical Journal</i>, vol. 162, no. 5, 209, IOP Publishing, 2021, doi:<a href="https://doi.org/10.3847/1538-3881/ac166a">10.3847/1538-3881/ac166a</a>.'
  short: J. Audenaert, J.S. Kuszlewicz, R. Handberg, A. Tkachenko, D.J. Armstrong,
    M. Hon, R. Kgoadi, M.N. Lund, K.J. Bell, L.A. Bugnet, D.M. Bowman, C. Johnston,
    R.A. García, D. Stello, L. Molnár, E. Plachy, D. Buzasi, C. Aerts, The Astronomical
    Journal 162 (2021).
date_created: 2022-07-18T11:54:55Z
date_published: 2021-10-21T00:00:00Z
date_updated: 2022-08-19T10:01:56Z
day: '21'
doi: 10.3847/1538-3881/ac166a
extern: '1'
external_id:
  arxiv:
  - '2107.06301'
intvolume: '       162'
issue: '5'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2107.06301
month: '10'
oa: 1
oa_version: Preprint
publication: The Astronomical Journal
publication_identifier:
  eissn:
  - 1538-3881
  issn:
  - 0004-6256
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'TESS Data for Asteroseismology (T’DA) stellar variability classification pipeline:
  Setup and application to the Kepler Q9 data'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 162
year: '2021'
...
---
_id: '11605'
abstract:
- lang: eng
  text: "Context. The discovery of moderate differential rotation between the core
    and the envelope of evolved solar-like stars could be the signature of a strong
    magnetic field trapped inside the radiative interior. The population of intermediate-mass
    red giants presenting surprisingly low-amplitude mixed modes (i.e. oscillation
    modes that behave as acoustic modes in their external envelope and as gravity
    modes in their core) could also arise from the effect of an internal magnetic
    field. Indeed, stars more massive than about 1.1 solar masses are known to develop
    a convective core during their main sequence. The field generated by the dynamo
    triggered by this convection could be the progenitor of a strong fossil magnetic
    field trapped inside the core of the star for the remainder of its evolution.\r\n\r\nAims.
    Observations of mixed modes can constitute an excellent probe of the deepest layers
    of evolved solar-like stars, and magnetic fields in those regions can impact their
    propagation. The magnetic perturbation on mixed modes may therefore be visible
    in asteroseismic data. To unravel which constraints can be obtained from observations,
    we theoretically investigate the effects of a plausible mixed axisymmetric magnetic
    field with various amplitudes on the mixed-mode frequencies of evolved solar-like
    stars.\r\n\r\nMethods. First-order frequency perturbations due to an axisymmetric
    magnetic field were computed for dipolar and quadrupolar mixed modes. These computations
    were carried out for a range of stellar ages, masses, and metallicities.\r\n\r\nConclusions.
    We show that typical fossil-field strengths of 0.1 − 1 MG, consistent with the
    presence of a dynamo in the convective core during the main sequence, provoke
    significant asymmetries on mixed-mode frequency multiplets during the red giant
    branch. We provide constraints and methods for the detectability of such magnetic
    signatures. We show that these signatures may be detectable in asteroseismic data
    for field amplitudes small enough for the amplitude of the modes not to be affected
    by the conversion of gravity into Alfvén waves inside the magnetised interior.
    Finally, we infer an upper limit for the strength of the field and the associated
    lower limit for the timescale of its action in order to redistribute angular momentum
    in stellar interiors."
article_number: A53
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: V.
  full_name: Prat, V.
  last_name: Prat
- first_name: S.
  full_name: Mathis, S.
  last_name: Mathis
- first_name: A.
  full_name: Astoul, A.
  last_name: Astoul
- first_name: K.
  full_name: Augustson, K.
  last_name: Augustson
- first_name: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: L.
  full_name: Amard, L.
  last_name: Amard
- first_name: C.
  full_name: Neiner, C.
  last_name: Neiner
citation:
  ama: 'Bugnet LA, Prat V, Mathis S, et al. Magnetic signatures on mixed-mode frequencies:
    I. An axisymmetric fossil field inside the core of red giants. <i>Astronomy &#38;
    Astrophysics</i>. 2021;650. doi:<a href="https://doi.org/10.1051/0004-6361/202039159">10.1051/0004-6361/202039159</a>'
  apa: 'Bugnet, L. A., Prat, V., Mathis, S., Astoul, A., Augustson, K., García, R.
    A., … Neiner, C. (2021). Magnetic signatures on mixed-mode frequencies: I. An
    axisymmetric fossil field inside the core of red giants. <i>Astronomy &#38; Astrophysics</i>.
    EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202039159">https://doi.org/10.1051/0004-6361/202039159</a>'
  chicago: 'Bugnet, Lisa Annabelle, V. Prat, S. Mathis, A. Astoul, K. Augustson, R.
    A. García, S. Mathur, L. Amard, and C. Neiner. “Magnetic Signatures on Mixed-Mode
    Frequencies: I. An Axisymmetric Fossil Field inside the Core of Red Giants.” <i>Astronomy
    &#38; Astrophysics</i>. EDP Sciences, 2021. <a href="https://doi.org/10.1051/0004-6361/202039159">https://doi.org/10.1051/0004-6361/202039159</a>.'
  ieee: 'L. A. Bugnet <i>et al.</i>, “Magnetic signatures on mixed-mode frequencies:
    I. An axisymmetric fossil field inside the core of red giants,” <i>Astronomy &#38;
    Astrophysics</i>, vol. 650. EDP Sciences, 2021.'
  ista: 'Bugnet LA, Prat V, Mathis S, Astoul A, Augustson K, García RA, Mathur S,
    Amard L, Neiner C. 2021. Magnetic signatures on mixed-mode frequencies: I. An
    axisymmetric fossil field inside the core of red giants. Astronomy &#38; Astrophysics.
    650, A53.'
  mla: 'Bugnet, Lisa Annabelle, et al. “Magnetic Signatures on Mixed-Mode Frequencies:
    I. An Axisymmetric Fossil Field inside the Core of Red Giants.” <i>Astronomy &#38;
    Astrophysics</i>, vol. 650, A53, EDP Sciences, 2021, doi:<a href="https://doi.org/10.1051/0004-6361/202039159">10.1051/0004-6361/202039159</a>.'
  short: L.A. Bugnet, V. Prat, S. Mathis, A. Astoul, K. Augustson, R.A. García, S.
    Mathur, L. Amard, C. Neiner, Astronomy &#38; Astrophysics 650 (2021).
date_created: 2022-07-18T12:10:59Z
date_published: 2021-06-07T00:00:00Z
date_updated: 2022-08-19T10:06:33Z
day: '07'
doi: 10.1051/0004-6361/202039159
extern: '1'
external_id:
  arxiv:
  - '2102.01216'
intvolume: '       650'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- stars
- oscillations / stars
- magnetic field / stars
- interiors / stars
- evolution / stars
- rotation
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2102.01216
month: '06'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Magnetic signatures on mixed-mode frequencies: I. An axisymmetric fossil field
  inside the core of red giants'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 650
year: '2021'
...
---
_id: '11606'
abstract:
- lang: eng
  text: "Context. Our knowledge of the dynamics of stars has undergone a revolution
    through the simultaneous large amount of high-quality photometric observations
    collected by space-based asteroseismology and ground-based high-precision spectropolarimetry.
    They allowed us to probe the internal rotation of stars and their surface magnetism
    in the whole Hertzsprung-Russell diagram. However, new methods should still be
    developed to probe the deep magnetic fields in these stars.\r\n\r\nAims. Our goal
    is to provide seismic diagnoses that allow us to probe the internal magnetism
    of stars.\r\n\r\nMethods. We focused on asymptotic low-frequency gravity modes
    and high-frequency acoustic modes. Using a first-order perturbative theory, we
    derived magnetic splittings of their frequencies as explicit functions of stellar
    parameters.\r\n\r\nResults. As in the case of rotation, we show that asymptotic
    gravity and acoustic modes can allow us to probe the different components of the
    magnetic field in the cavities in which they propagate. This again demonstrates
    the high potential of using mixed-modes when this is possible."
acknowledgement: The authors thank the referee and Pr. J. Christensen-Dalsgaard for
  their very constructive comments and remarks that allowed us to improve the article.
  St. M., L. B., V. P., and K. A. acknowledge support from the European Research Council
  through ERC grant SPIRE 647383. All the members from CEA acknowledge support from
  GOLF and PLATO CNES grants of the Astrophysics Division at CEA. S. Mathur acknowledges
  support by the Ramon y Cajal fellowship number RYC-2015-17697. We made great use
  of the megyr python package for interfacing MESA and GYRE codes.
article_number: A122
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: S.
  full_name: Mathis, S.
  last_name: Mathis
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: V.
  full_name: Prat, V.
  last_name: Prat
- first_name: K.
  full_name: Augustson, K.
  last_name: Augustson
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: R. A.
  full_name: Garcia, R. A.
  last_name: Garcia
citation:
  ama: Mathis S, Bugnet LA, Prat V, Augustson K, Mathur S, Garcia RA. Probing the
    internal magnetism of stars using asymptotic magneto-asteroseismology. <i>Astronomy
    &#38; Astrophysics</i>. 2021;647. doi:<a href="https://doi.org/10.1051/0004-6361/202039180">10.1051/0004-6361/202039180</a>
  apa: Mathis, S., Bugnet, L. A., Prat, V., Augustson, K., Mathur, S., &#38; Garcia,
    R. A. (2021). Probing the internal magnetism of stars using asymptotic magneto-asteroseismology.
    <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202039180">https://doi.org/10.1051/0004-6361/202039180</a>
  chicago: Mathis, S., Lisa Annabelle Bugnet, V. Prat, K. Augustson, S. Mathur, and
    R. A. Garcia. “Probing the Internal Magnetism of Stars Using Asymptotic Magneto-Asteroseismology.”
    <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2021. <a href="https://doi.org/10.1051/0004-6361/202039180">https://doi.org/10.1051/0004-6361/202039180</a>.
  ieee: S. Mathis, L. A. Bugnet, V. Prat, K. Augustson, S. Mathur, and R. A. Garcia,
    “Probing the internal magnetism of stars using asymptotic magneto-asteroseismology,”
    <i>Astronomy &#38; Astrophysics</i>, vol. 647. EDP Sciences, 2021.
  ista: Mathis S, Bugnet LA, Prat V, Augustson K, Mathur S, Garcia RA. 2021. Probing
    the internal magnetism of stars using asymptotic magneto-asteroseismology. Astronomy
    &#38; Astrophysics. 647, A122.
  mla: Mathis, S., et al. “Probing the Internal Magnetism of Stars Using Asymptotic
    Magneto-Asteroseismology.” <i>Astronomy &#38; Astrophysics</i>, vol. 647, A122,
    EDP Sciences, 2021, doi:<a href="https://doi.org/10.1051/0004-6361/202039180">10.1051/0004-6361/202039180</a>.
  short: S. Mathis, L.A. Bugnet, V. Prat, K. Augustson, S. Mathur, R.A. Garcia, Astronomy
    &#38; Astrophysics 647 (2021).
date_created: 2022-07-18T12:15:27Z
date_published: 2021-03-18T00:00:00Z
date_updated: 2022-08-19T10:11:52Z
day: '18'
doi: 10.1051/0004-6361/202039180
extern: '1'
external_id:
  arxiv:
  - '2012.11050'
intvolume: '       647'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- asteroseismology / waves / stars
- magnetic field / stars
- oscillations / methods
- analytical
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2012.11050
month: '03'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: Probing the internal magnetism of stars using asymptotic magneto-asteroseismology
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 647
year: '2021'
...
---
_id: '11608'
abstract:
- lang: eng
  text: 'In order to understand stellar evolution, it is crucial to efficiently determine
    stellar surface rotation periods. Indeed, while they are of great importance in
    stellar models, angular momentum transport processes inside stars are still poorly
    understood today. Surface rotation, which is linked to the age of the star, is
    one of the constraints needed to improve the way those processes are modelled.
    Statistics of the surface rotation periods for a large sample of stars of different
    spectral types are thus necessary. An efficient tool to automatically determine
    reliable rotation periods is needed when dealing with large samples of stellar
    photometric datasets. The objective of this work is to develop such a tool. For
    this purpose, machine learning classifiers constitute relevant bases to build
    our new methodology. Random forest learning abilities are exploited to automate
    the extraction of rotation periods in Kepler light curves. Rotation periods and
    complementary parameters are obtained via three different methods: a wavelet analysis,
    the autocorrelation function of the light curve, and the composite spectrum. We
    trained three different classifiers: one to detect if rotational modulations are
    present in the light curve, one to flag close binary or classical pulsators candidates
    that can bias our rotation period determination, and finally one classifier to
    provide the final rotation period. We tested our machine learning pipeline on
    23 431 stars of the Kepler K and M dwarf reference rotation catalogue for which
    60% of the stars have been visually inspected. For the sample of 21 707 stars
    where all the input parameters are provided to the algorithm, 94.2% of them are
    correctly classified (as rotating or not). Among the stars that have a rotation
    period in the reference catalogue, the machine learning provides a period that
    agrees within 10% of the reference value for 95.3% of the stars. Moreover, the
    yield of correct rotation periods is raised to 99.5% after visually inspecting
    25.2% of the stars. Over the two main analysis steps, rotation classification
    and period selection, the pipeline yields a global agreement with the reference
    values of 92.1% and 96.9% before and after visual inspection. Random forest classifiers
    are efficient tools to determine reliable rotation periods in large samples of
    stars. The methodology presented here could be easily adapted to extract surface
    rotation periods for stars with different spectral types or observed by other
    instruments such as K2, TESS or by PLATO in the near future.'
acknowledgement: 'We thank Suzanne Aigrain and Joe Llama for providing us with the
  simulated data used in Aigrain et al. (2015). S. N. B., L. B. and R. A. G. acknowledge
  the support from PLATO and GOLF CNES grants. A. R. G. S. acknowledges the support
  from NASA under grant NNX17AF27G. S. M. acknowledges the support from the Spanish
  Ministry of Science and Innovation with the Ramon y Cajal fellowship number RYC-2015-17697.
  P. L. P. and S. M. acknowledge support from the Spanish Ministry of Science and
  Innovation with the grant number PID2019-107187GB-I00. This research has made use
  of the NASA Exoplanet Archive, which is operated by the California Institute of
  Technology, under contract with the National Aeronautics and Space Administration
  under the Exoplanet Exploration Program. Software: Python (Van Rossum & Drake 2009),
  numpy (Oliphant 2006), pandas (The pandas development team 2020; McKinney 2010),
  matplotlib (Hunter 2007), scikit-learn (Pedregosa et al. 2011). The source code
  used to obtain the present results can be found at: https://gitlab.com/sybreton/pushkin
  ; https://gitlab.com/sybreton/ml_surface_rotation_paper .'
article_number: A125
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: S. N.
  full_name: Breton, S. N.
  last_name: Breton
- first_name: A. R. G.
  full_name: Santos, A. R. G.
  last_name: Santos
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: P. L.
  full_name: Pallé, P. L.
  last_name: Pallé
citation:
  ama: 'Breton SN, Santos ARG, Bugnet LA, Mathur S, García RA, Pallé PL. ROOSTER:
    A machine-learning analysis tool for Kepler stellar rotation periods. <i>Astronomy
    &#38; Astrophysics</i>. 2021;647. doi:<a href="https://doi.org/10.1051/0004-6361/202039947">10.1051/0004-6361/202039947</a>'
  apa: 'Breton, S. N., Santos, A. R. G., Bugnet, L. A., Mathur, S., García, R. A.,
    &#38; Pallé, P. L. (2021). ROOSTER: A machine-learning analysis tool for Kepler
    stellar rotation periods. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a
    href="https://doi.org/10.1051/0004-6361/202039947">https://doi.org/10.1051/0004-6361/202039947</a>'
  chicago: 'Breton, S. N., A. R. G. Santos, Lisa Annabelle Bugnet, S. Mathur, R. A.
    García, and P. L. Pallé. “ROOSTER: A Machine-Learning Analysis Tool for Kepler
    Stellar Rotation Periods.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences,
    2021. <a href="https://doi.org/10.1051/0004-6361/202039947">https://doi.org/10.1051/0004-6361/202039947</a>.'
  ieee: 'S. N. Breton, A. R. G. Santos, L. A. Bugnet, S. Mathur, R. A. García, and
    P. L. Pallé, “ROOSTER: A machine-learning analysis tool for Kepler stellar rotation
    periods,” <i>Astronomy &#38; Astrophysics</i>, vol. 647. EDP Sciences, 2021.'
  ista: 'Breton SN, Santos ARG, Bugnet LA, Mathur S, García RA, Pallé PL. 2021. ROOSTER:
    A machine-learning analysis tool for Kepler stellar rotation periods. Astronomy
    &#38; Astrophysics. 647, A125.'
  mla: 'Breton, S. N., et al. “ROOSTER: A Machine-Learning Analysis Tool for Kepler
    Stellar Rotation Periods.” <i>Astronomy &#38; Astrophysics</i>, vol. 647, A125,
    EDP Sciences, 2021, doi:<a href="https://doi.org/10.1051/0004-6361/202039947">10.1051/0004-6361/202039947</a>.'
  short: S.N. Breton, A.R.G. Santos, L.A. Bugnet, S. Mathur, R.A. García, P.L. Pallé,
    Astronomy &#38; Astrophysics 647 (2021).
date_created: 2022-07-18T12:21:32Z
date_published: 2021-03-19T00:00:00Z
date_updated: 2022-08-22T08:47:47Z
day: '19'
doi: 10.1051/0004-6361/202039947
extern: '1'
external_id:
  arxiv:
  - '2101.10152'
intvolume: '       647'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'methods: data analysis / stars: solar-type / stars: activity / stars: rotation
  / starspots'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2101.10152
month: '03'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'ROOSTER: A machine-learning analysis tool for Kepler stellar rotation periods'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 647
year: '2021'
...
---
_id: '11609'
abstract:
- lang: eng
  text: "Context. Stellar interiors are the seat of efficient transport of angular
    momentum all along their evolution. In this context, understanding the dependence
    of the turbulent transport triggered by the instabilities of the vertical and
    horizontal shears of the differential rotation in stellar radiation zones as a
    function of their rotation, stratification, and thermal diffusivity is mandatory.
    Indeed, it constitutes one of the cornerstones of the rotational transport and
    mixing theory, which is implemented in stellar evolution codes to predict the
    rotational and chemical evolutions of stars.\r\n\r\nAims. We investigate horizontal
    shear instabilities in rotating stellar radiation zones by considering the full
    Coriolis acceleration with both the dimensionless horizontal Coriolis component
    f̃ and the vertical component f.\r\n\r\nMethods. We performed a linear stability
    analysis using linearized equations derived from the Navier-Stokes and heat transport
    equations in the rotating nontraditional f-plane. We considered a horizontal shear
    flow with a hyperbolic tangent profile as the base flow. The linear stability
    was analyzed numerically in wide ranges of parameters, and we performed an asymptotic
    analysis for large vertical wavenumbers using the Wentzel-Kramers-Brillouin-Jeffreys
    (WKBJ) approximation for nondiffusive and highly-diffusive fluids.\r\n\r\nResults.
    As in the traditional f-plane approximation, we identify two types of instabilities:
    the inflectional and inertial instabilities. The inflectional instability is destabilized
    as f̃ increases and its maximum growth rate increases significantly, while the
    thermal diffusivity stabilizes the inflectional instability similarly to the traditional
    case. The inertial instability is also strongly affected; for instance, the inertially
    unstable regime is also extended in the nondiffusive limit as 0 < f < 1 + f̃ 2/N2,
    where N is the dimensionless Brunt-Väisälä frequency. More strikingly, in the
    high thermal diffusivity limit, it is always inertially unstable at any colatitude
    θ except at the poles (i.e., 0° < θ <  180°). We also derived the critical Reynolds
    numbers for the inertial instability using the asymptotic dispersion relations
    obtained from the WKBJ analysis. Using the asymptotic and numerical results, we
    propose a prescription for the effective turbulent viscosities induced by the
    inertial and inflectional instabilities that can be possibly used in stellar evolution
    models. The characteristic time of this turbulence is short enough so that it
    is efficient to redistribute angular momentum and to mix chemicals in stellar
    radiation zones."
acknowledgement: The authors acknowledge support from the European Research Council
  through ERC grant SPIRE 647383 and from GOLF and PLATO CNES grants at the Department
  of Astrophysics at CEA Paris-Saclay. We thank the referee, Prof. A. J. Barker, for
  his constructive comments that allow us to improve the article.
article_number: A64
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: J.
  full_name: Park, J.
  last_name: Park
- first_name: V.
  full_name: Prat, V.
  last_name: Prat
- first_name: S.
  full_name: Mathis, S.
  last_name: Mathis
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
citation:
  ama: 'Park J, Prat V, Mathis S, Bugnet LA. Horizontal shear instabilities in rotating
    stellar radiation zones: II. Effects of the full Coriolis acceleration. <i>Astronomy
    &#38; Astrophysics</i>. 2021;646. doi:<a href="https://doi.org/10.1051/0004-6361/202038654">10.1051/0004-6361/202038654</a>'
  apa: 'Park, J., Prat, V., Mathis, S., &#38; Bugnet, L. A. (2021). Horizontal shear
    instabilities in rotating stellar radiation zones: II. Effects of the full Coriolis
    acceleration. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202038654">https://doi.org/10.1051/0004-6361/202038654</a>'
  chicago: 'Park, J., V. Prat, S. Mathis, and Lisa Annabelle Bugnet. “Horizontal Shear
    Instabilities in Rotating Stellar Radiation Zones: II. Effects of the Full Coriolis
    Acceleration.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2021. <a href="https://doi.org/10.1051/0004-6361/202038654">https://doi.org/10.1051/0004-6361/202038654</a>.'
  ieee: 'J. Park, V. Prat, S. Mathis, and L. A. Bugnet, “Horizontal shear instabilities
    in rotating stellar radiation zones: II. Effects of the full Coriolis acceleration,”
    <i>Astronomy &#38; Astrophysics</i>, vol. 646. EDP Sciences, 2021.'
  ista: 'Park J, Prat V, Mathis S, Bugnet LA. 2021. Horizontal shear instabilities
    in rotating stellar radiation zones: II. Effects of the full Coriolis acceleration.
    Astronomy &#38; Astrophysics. 646, A64.'
  mla: 'Park, J., et al. “Horizontal Shear Instabilities in Rotating Stellar Radiation
    Zones: II. Effects of the Full Coriolis Acceleration.” <i>Astronomy &#38; Astrophysics</i>,
    vol. 646, A64, EDP Sciences, 2021, doi:<a href="https://doi.org/10.1051/0004-6361/202038654">10.1051/0004-6361/202038654</a>.'
  short: J. Park, V. Prat, S. Mathis, L.A. Bugnet, Astronomy &#38; Astrophysics 646
    (2021).
date_created: 2022-07-18T13:24:32Z
date_published: 2021-02-08T00:00:00Z
date_updated: 2022-08-19T10:18:03Z
day: '08'
doi: 10.1051/0004-6361/202038654
extern: '1'
external_id:
  arxiv:
  - '2006.10660'
intvolume: '       646'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- hydrodynamics / turbulence / stars
- rotation / stars
- evolution
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2006.10660
month: '02'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Sciences
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Horizontal shear instabilities in rotating stellar radiation zones: II. Effects
  of the full Coriolis acceleration'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 646
year: '2021'
...
---
_id: '11610'
abstract:
- lang: eng
  text: Studies of Galactic structure and evolution have benefited enormously from
    Gaia kinematic information, though additional, intrinsic stellar parameters like
    age are required to best constrain Galactic models. Asteroseismology is the most
    precise method of providing such information for field star populations en masse,
    but existing samples for the most part have been limited to a few narrow fields
    of view by the CoRoT and Kepler missions. In an effort to provide well-characterized
    stellar parameters across a wide range in Galactic position, we present the second
    data release of red giant asteroseismic parameters for the K2 Galactic Archaeology
    Program (GAP). We provide ${\nu }_{\max }$ and ${\rm{\Delta }}\nu $ based on six
    independent pipeline analyses; first-ascent red giant branch (RGB) and red clump
    (RC) evolutionary state classifications from machine learning; and ready-to-use
    radius and mass coefficients, κR and κM, which, when appropriately multiplied
    by a solar-scaled effective temperature factor, yield physical stellar radii and
    masses. In total, we report 4395 radius and mass coefficients, with typical uncertainties
    of 3.3% (stat.) ± 1% (syst.) for κR and 7.7% (stat.) ± 2% (syst.) for κM among
    RGB stars, and 5.0% (stat.) ± 1% (syst.) for κR and 10.5% (stat.) ± 2% (syst.)
    for κM among RC stars. We verify that the sample is nearly complete—except for
    a dearth of stars with ${\nu }_{\max }\lesssim 10\mbox{--}20\,\mu \mathrm{Hz}$—by
    comparing to Galactic models and visual inspection. Our asteroseismic radii agree
    with radii derived from Gaia Data Release 2 parallaxes to within 2.2% ± 0.3% for
    RGB stars and 2.0% ± 0.6% for RC stars.
acknowledgement: "We thank the referee for comments that strengthened the manuscript.
  J. C. Z. and M. H. P. acknowledge support from NASA grants 80NSSC18K0391 and NNX17AJ40G.
  Y. E. and C. J. acknowledge the support of the UK Science and Technology Facilities
  Council (STFC). S. M. would like to acknowledge support from the Spanish Ministry
  with the Ramon y Cajal fellowship number RYC-2015-17697. R. A. G. acknowledges funding
  received from the PLATO CNES grant. R. S. acknowledges funding via a Royal Society
  University Research Fellowship. D.H. acknowledges support from the Alfred P. Sloan
  Foundation and the National Aeronautics and Space Administration (80NSSC19K0108).
  V.S.A. acknowledges support from the Independent Research Fund Denmark (Research
  grant 7027-00096B), and the Carlsberg foundation (grant agreement CF19-0649). This
  research was supported in part by the National Science Foundation under grant No.
  NSF PHY-1748958.\r\n\r\nFunding for the Stellar Astrophysics Centre (SAC) is provided
  by The Danish National Research Foundation (grant agreement No. DNRF106).\r\n\r\nThe
  K2 Galactic Archaeology Program is supported by the National Aeronautics and Space
  Administration under grant NNX16AJ17G issued through the K2 Guest Observer Program.\r\n\r\nThis
  publication makes use of data products from the Two Micron All Sky Survey, which
  is a joint project of the University of Massachusetts and the Infrared Processing
  and Analysis Center/California Institute of Technology, funded by the National Aeronautics
  and Space Administration and the National Science Foundation.\r\n\r\nThis work has
  made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia),
  processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).
  Funding for the DPAC has been provided by national institutions, in particular the
  institutions participating in the Gaia Multilateral Agreement.\r\n\r\nFunding for
  the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation,
  the U.S. Department of Energy Office of Science, and the Participating Institutions.
  SDSS-IV acknowledges support and resources from the Center for High Performance
  Computing at the University of Utah. The SDSS website is www.sdss.org.\r\n\r\nSDSS-IV
  is managed by the Astrophysical Research Consortium for the Participating Institutions
  of the SDSS Collaboration, including the Brazilian Participation Group, the Carnegie
  Institution for Science, Carnegie Mellon University, the Chilean Participation Group,
  the French Participation Group, the Harvard–Smithsonian Center for Astrophysics,
  Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute
  for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, the
  Korean Participation Group, Lawrence Berkeley National Laboratory, Leibniz Institut
  für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg),
  Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische
  Physik (MPE), National Astronomical Observatories of China, New Mexico State University,
  New York University, University of Notre Dame, Observatário Nacional/MCTI, The Ohio
  State University, Pennsylvania State University, Shanghai Astronomical Observatory,
  United Kingdom Participation Group, Universidad Nacional Autónoma de México, University
  of Arizona, University of Colorado Boulder, University of Oxford, University of
  Portsmouth, University of Utah, University of Virginia, University of Washington,
  University of Wisconsin, Vanderbilt University, and Yale University.\r\n\r\nSoftware:
  asfgrid (Sharma & Stello 2016), emcee (Foreman-Mackey et al. 2013), NumPy (Walt
  2011), pandas (McKinney 2010; Reback et al. 2020), Matplotlib (Hunter 2007), IPython
  (Pérez & Granger 2007), SciPy (Virtanen et al. 2020)."
article_number: '23'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Joel C.
  full_name: Zinn, Joel C.
  last_name: Zinn
- first_name: Dennis
  full_name: Stello, Dennis
  last_name: Stello
- first_name: Yvonne
  full_name: Elsworth, Yvonne
  last_name: Elsworth
- first_name: Rafael A.
  full_name: García, Rafael A.
  last_name: García
- first_name: Thomas
  full_name: Kallinger, Thomas
  last_name: Kallinger
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Benoît
  full_name: Mosser, Benoît
  last_name: Mosser
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Caitlin
  full_name: Jones, Caitlin
  last_name: Jones
- first_name: Marc
  full_name: Hon, Marc
  last_name: Hon
- first_name: Sanjib
  full_name: Sharma, Sanjib
  last_name: Sharma
- first_name: Ralph
  full_name: Schönrich, Ralph
  last_name: Schönrich
- first_name: Jack T.
  full_name: Warfield, Jack T.
  last_name: Warfield
- first_name: Rodrigo
  full_name: Luger, Rodrigo
  last_name: Luger
- first_name: Marc H.
  full_name: Pinsonneault, Marc H.
  last_name: Pinsonneault
- first_name: Jennifer A.
  full_name: Johnson, Jennifer A.
  last_name: Johnson
- first_name: Daniel
  full_name: Huber, Daniel
  last_name: Huber
- first_name: Victor Silva
  full_name: Aguirre, Victor Silva
  last_name: Aguirre
- first_name: William J.
  full_name: Chaplin, William J.
  last_name: Chaplin
- first_name: Guy R.
  full_name: Davies, Guy R.
  last_name: Davies
- first_name: Andrea
  full_name: Miglio, Andrea
  last_name: Miglio
citation:
  ama: 'Zinn JC, Stello D, Elsworth Y, et al. The K2 galactic archaeology program
    data release 2: Asteroseismic results from campaigns 4, 6, and 7. <i>The Astrophysical
    Journal Supplement Series</i>. 2020;251(2). doi:<a href="https://doi.org/10.3847/1538-4365/abbee3">10.3847/1538-4365/abbee3</a>'
  apa: 'Zinn, J. C., Stello, D., Elsworth, Y., García, R. A., Kallinger, T., Mathur,
    S., … Miglio, A. (2020). The K2 galactic archaeology program data release 2: Asteroseismic
    results from campaigns 4, 6, and 7. <i>The Astrophysical Journal Supplement Series</i>.
    IOP Publishing. <a href="https://doi.org/10.3847/1538-4365/abbee3">https://doi.org/10.3847/1538-4365/abbee3</a>'
  chicago: 'Zinn, Joel C., Dennis Stello, Yvonne Elsworth, Rafael A. García, Thomas
    Kallinger, Savita Mathur, Benoît Mosser, et al. “The K2 Galactic Archaeology Program
    Data Release 2: Asteroseismic Results from Campaigns 4, 6, and 7.” <i>The Astrophysical
    Journal Supplement Series</i>. IOP Publishing, 2020. <a href="https://doi.org/10.3847/1538-4365/abbee3">https://doi.org/10.3847/1538-4365/abbee3</a>.'
  ieee: 'J. C. Zinn <i>et al.</i>, “The K2 galactic archaeology program data release
    2: Asteroseismic results from campaigns 4, 6, and 7,” <i>The Astrophysical Journal
    Supplement Series</i>, vol. 251, no. 2. IOP Publishing, 2020.'
  ista: 'Zinn JC, Stello D, Elsworth Y, García RA, Kallinger T, Mathur S, Mosser B,
    Bugnet LA, Jones C, Hon M, Sharma S, Schönrich R, Warfield JT, Luger R, Pinsonneault
    MH, Johnson JA, Huber D, Aguirre VS, Chaplin WJ, Davies GR, Miglio A. 2020. The
    K2 galactic archaeology program data release 2: Asteroseismic results from campaigns
    4, 6, and 7. The Astrophysical Journal Supplement Series. 251(2), 23.'
  mla: 'Zinn, Joel C., et al. “The K2 Galactic Archaeology Program Data Release 2:
    Asteroseismic Results from Campaigns 4, 6, and 7.” <i>The Astrophysical Journal
    Supplement Series</i>, vol. 251, no. 2, 23, IOP Publishing, 2020, doi:<a href="https://doi.org/10.3847/1538-4365/abbee3">10.3847/1538-4365/abbee3</a>.'
  short: J.C. Zinn, D. Stello, Y. Elsworth, R.A. García, T. Kallinger, S. Mathur,
    B. Mosser, L.A. Bugnet, C. Jones, M. Hon, S. Sharma, R. Schönrich, J.T. Warfield,
    R. Luger, M.H. Pinsonneault, J.A. Johnson, D. Huber, V.S. Aguirre, W.J. Chaplin,
    G.R. Davies, A. Miglio, The Astrophysical Journal Supplement Series 251 (2020).
date_created: 2022-07-18T13:27:26Z
date_published: 2020-12-01T00:00:00Z
date_updated: 2022-08-22T07:04:45Z
day: '01'
doi: 10.3847/1538-4365/abbee3
extern: '1'
external_id:
  arxiv:
  - '2012.04051'
intvolume: '       251'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2012.04051
month: '12'
oa: 1
oa_version: Preprint
publication: The Astrophysical Journal Supplement Series
publication_identifier:
  eissn:
  - 1538-4365
  issn:
  - 0067-0049
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'The K2 galactic archaeology program data release 2: Asteroseismic results
  from campaigns 4, 6, and 7'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 251
year: '2020'
...
---
_id: '11611'
abstract:
- lang: eng
  text: Over the course of its history, the Milky Way has ingested multiple smaller
    satellite galaxies1. Although these accreted stellar populations can be forensically
    identified as kinematically distinct structures within the Galaxy, it is difficult
    in general to date precisely the age at which any one merger occurred. Recent
    results have revealed a population of stars that were accreted via the collision
    of a dwarf galaxy, called Gaia–Enceladus1, leading to substantial pollution of
    the chemical and dynamical properties of the Milky Way. Here we identify the very
    bright, naked-eye star ν Indi as an indicator of the age of the early in situ
    population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric
    and kinematic observations to show that this metal-poor, alpha-element-rich star
    was an indigenous member of the halo, and we measure its age to be 11.0±0.7 (stat)
    ±0.8 (sys) billion years. The star bears hallmarks consistent with having been
    kinematically heated by the Gaia–Enceladus collision. Its age implies that the
    earliest the merger could have begun was 11.6 and 13.2 billion years ago, at 68%
    and 95% confidence, respectively. Computations based on hierarchical cosmological
    models slightly reduce the above limits.
acknowledgement: This paper includes data collected by the TESS mission, which are
  publicly available from the Mikulski Archive for Space Telescopes (MAST). Resources
  supporting this work were provided by the NASA High-End Computing (HEC) Program
  through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center
  for the production of the SPOC data products. W.J.C. acknowledges support from the
  UK Science and Technology Facilities Council (STFC) and UK Space Agency. Funding
  for the Stellar Astrophysics Centre is provided by The Danish National Research
  Foundation (grant agreement number DNRF106). This research was partially conducted
  during the Exostar19 programme at the Kavli Institute for Theoretical Physics at
  UC Santa Barbara, which was supported in part by the National Science Foundation
  under grant number NSF PHY-1748958. A.M., J.T.M., F.V. and J.M. acknowledge support
  from the ERC Consolidator Grant funding scheme (project ASTEROCHRONOMETRY, grant
  agreement number 772293). F.V. acknowledges the support of a Fellowship from the
  Center for Cosmology and AstroParticle Physics at The Ohio State University. W.H.B.
  and M.B.N. acknowledge support from the UK Space Agency. K.J.B. is supported by
  the National Science Foundation under award AST-1903828. M.B.N. acknowledges partial
  support from the NYU Abu Dhabi Center for Space Science under grant number G1502.
  A.M.S. is partially supported by the Spanish Government (ESP2017-82674-R) and Generalitat
  de Catalunya (2017-SGR-1131). T.M. acknowledges financial support from Belspo for
  contract PRODEX PLATO. H.K. acknowledges support from the European Social Fund via
  the Lithuanian Science Council grant number 09.3.3-LMT-K-712-01-0103. S.B. acknowledges
  support from NSF grant AST-1514676 and NASA grant 80NSSC19K0374. V.S.A. acknowledges
  support from the Independent Research Fund Denmark (research grant 7027-00096B).
  D.H. acknowledges support by the National Aeronautics and Space Administration (80NSSC18K1585,
  80NSSC19K0379) awarded through the TESS Guest Investigator Program and by the National
  Science Foundation (AST-1717000). T.S.M. acknowledges support from a visiting fellowship
  at the Max Planck Institute for Solar System Research. Computational resources were
  provided through XSEDE allocation TG-AST090107. D.L.B. acknowledges support from
  NASA under grant NNX16AB76G. T.L.C. acknowledges support from the European Union’s
  Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie
  grant agreement number 792848 (PULSATION). This work was supported by FCT/MCTES
  through national funds (PIDDAC) by means of grant UID/FIS/04434/2019. K.J.B., S.H.,
  J.S.K. and N.T. are supported by the European Research Council under the European
  Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement number
  338251 (StellarAges). E.C. is funded by the European Union’s Horizon 2020 research
  and innovation program under the Marie Sklodowska-Curie grant agreement number 664931.
  L.G.-C. acknowledges support from the MINECO FPI-SO doctoral research project SEV-2015-0548-17-2
  and predoctoral contract BES-2017-082610. P.G. is supported by the German space
  agency (Deutsches Zentrum für Luft- und Raumfahrt) under PLATO data grant 50OO1501.
  R.K. acknowledges support from the UK Science and Technology Facilities Council
  (STFC), under consolidated grant ST/L000733/1. M.S.L. is supported by the Carlsberg
  Foundation (grant agreement number CF17-076). Z.C.O., S.O. and M.Y. acknowledge
  support from the Scientific and Technological Research Council of Turkey (TÜBİTAK:118F352).
  S.M. acknowledges support from the Spanish ministry through the Ramon y Cajal fellowship
  number RYC-2015-17697. T.S.R. acknowledges financial support from Premiale 2015
  MITiC (PI B. Garilli). R.Sz. acknowledges the support from NKFIH grant project No.
  K-115709, and the Lendület program of the Hungarian Academy of Science (project
  number 2018-7/2019). J.T. acknowledges support was provided by NASA through the
  NASA Hubble Fellowship grant number 51424 awarded by the Space Telescope Science
  Institute, which is operated by the Association of Universities for Research in
  Astronomy, Inc., for NASA, under contract NAS5-26555. This work was supported by
  FEDER through COMPETE2020 (POCI-01-0145-FEDER-030389. A.M.B. acknowledges funding
  from the European Union’s Horizon 2020 research and innovation program under the
  Marie Sklodowska-Curie grant agreement No 749962 (project THOT). A.M. and P.R. acknowledge
  the support of the Government of India, Department of Atomic Energy, under Project
  No. 12-R&D-TFR-6.04-0600. K.J.B. is an NSF Astronomy and Astrophysics Postdoctoral
  Fellow and DIRAC Fellow.
article_processing_charge: No
article_type: letter_note
arxiv: 1
author:
- first_name: William J.
  full_name: Chaplin, William J.
  last_name: Chaplin
- first_name: Aldo M.
  full_name: Serenelli, Aldo M.
  last_name: Serenelli
- first_name: Andrea
  full_name: Miglio, Andrea
  last_name: Miglio
- first_name: Thierry
  full_name: Morel, Thierry
  last_name: Morel
- first_name: J. Ted
  full_name: Mackereth, J. Ted
  last_name: Mackereth
- first_name: Fiorenzo
  full_name: Vincenzo, Fiorenzo
  last_name: Vincenzo
- first_name: Hans
  full_name: Kjeldsen, Hans
  last_name: Kjeldsen
- first_name: Sarbani
  full_name: Basu, Sarbani
  last_name: Basu
- first_name: Warrick H.
  full_name: Ball, Warrick H.
  last_name: Ball
- first_name: Amalie
  full_name: Stokholm, Amalie
  last_name: Stokholm
- first_name: Kuldeep
  full_name: Verma, Kuldeep
  last_name: Verma
- first_name: Jakob Rørsted
  full_name: Mosumgaard, Jakob Rørsted
  last_name: Mosumgaard
- first_name: Victor
  full_name: Silva Aguirre, Victor
  last_name: Silva Aguirre
- first_name: Anwesh
  full_name: Mazumdar, Anwesh
  last_name: Mazumdar
- first_name: Pritesh
  full_name: Ranadive, Pritesh
  last_name: Ranadive
- first_name: H. M.
  full_name: Antia, H. M.
  last_name: Antia
- first_name: Yveline
  full_name: Lebreton, Yveline
  last_name: Lebreton
- first_name: Joel
  full_name: Ong, Joel
  last_name: Ong
- first_name: Thierry
  full_name: Appourchaux, Thierry
  last_name: Appourchaux
- first_name: Timothy R.
  full_name: Bedding, Timothy R.
  last_name: Bedding
- first_name: Jørgen
  full_name: Christensen-Dalsgaard, Jørgen
  last_name: Christensen-Dalsgaard
- first_name: Orlagh
  full_name: Creevey, Orlagh
  last_name: Creevey
- first_name: Rafael A.
  full_name: García, Rafael A.
  last_name: García
- first_name: Rasmus
  full_name: Handberg, Rasmus
  last_name: Handberg
- first_name: Daniel
  full_name: Huber, Daniel
  last_name: Huber
- first_name: Steven D.
  full_name: Kawaler, Steven D.
  last_name: Kawaler
- first_name: Mikkel N.
  full_name: Lund, Mikkel N.
  last_name: Lund
- first_name: Travis S.
  full_name: Metcalfe, Travis S.
  last_name: Metcalfe
- first_name: Keivan G.
  full_name: Stassun, Keivan G.
  last_name: Stassun
- first_name: Michäel
  full_name: Bazot, Michäel
  last_name: Bazot
- first_name: Paul G.
  full_name: Beck, Paul G.
  last_name: Beck
- first_name: Keaton J.
  full_name: Bell, Keaton J.
  last_name: Bell
- first_name: Maria
  full_name: Bergemann, Maria
  last_name: Bergemann
- first_name: Derek L.
  full_name: Buzasi, Derek L.
  last_name: Buzasi
- first_name: Othman
  full_name: Benomar, Othman
  last_name: Benomar
- first_name: Diego
  full_name: Bossini, Diego
  last_name: Bossini
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Tiago L.
  full_name: Campante, Tiago L.
  last_name: Campante
- first_name: Zeynep Çelik
  full_name: Orhan, Zeynep Çelik
  last_name: Orhan
- first_name: Enrico
  full_name: Corsaro, Enrico
  last_name: Corsaro
- first_name: Lucía
  full_name: González-Cuesta, Lucía
  last_name: González-Cuesta
- first_name: Guy R.
  full_name: Davies, Guy R.
  last_name: Davies
- first_name: Maria Pia
  full_name: Di Mauro, Maria Pia
  last_name: Di Mauro
- first_name: Ricky
  full_name: Egeland, Ricky
  last_name: Egeland
- first_name: Yvonne P.
  full_name: Elsworth, Yvonne P.
  last_name: Elsworth
- first_name: Patrick
  full_name: Gaulme, Patrick
  last_name: Gaulme
- first_name: Hamed
  full_name: Ghasemi, Hamed
  last_name: Ghasemi
- first_name: Zhao
  full_name: Guo, Zhao
  last_name: Guo
- first_name: Oliver J.
  full_name: Hall, Oliver J.
  last_name: Hall
- first_name: Amir
  full_name: Hasanzadeh, Amir
  last_name: Hasanzadeh
- first_name: Saskia
  full_name: Hekker, Saskia
  last_name: Hekker
- first_name: Rachel
  full_name: Howe, Rachel
  last_name: Howe
- first_name: Jon M.
  full_name: Jenkins, Jon M.
  last_name: Jenkins
- first_name: Antonio
  full_name: Jiménez, Antonio
  last_name: Jiménez
- first_name: René
  full_name: Kiefer, René
  last_name: Kiefer
- first_name: James S.
  full_name: Kuszlewicz, James S.
  last_name: Kuszlewicz
- first_name: Thomas
  full_name: Kallinger, Thomas
  last_name: Kallinger
- first_name: David W.
  full_name: Latham, David W.
  last_name: Latham
- first_name: Mia S.
  full_name: Lundkvist, Mia S.
  last_name: Lundkvist
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Josefina
  full_name: Montalbán, Josefina
  last_name: Montalbán
- first_name: Benoit
  full_name: Mosser, Benoit
  last_name: Mosser
- first_name: Andres Moya
  full_name: Bedón, Andres Moya
  last_name: Bedón
- first_name: Martin Bo
  full_name: Nielsen, Martin Bo
  last_name: Nielsen
- first_name: Sibel
  full_name: Örtel, Sibel
  last_name: Örtel
- first_name: Ben M.
  full_name: Rendle, Ben M.
  last_name: Rendle
- first_name: George R.
  full_name: Ricker, George R.
  last_name: Ricker
- first_name: Thaíse S.
  full_name: Rodrigues, Thaíse S.
  last_name: Rodrigues
- first_name: Ian W.
  full_name: Roxburgh, Ian W.
  last_name: Roxburgh
- first_name: Hossein
  full_name: Safari, Hossein
  last_name: Safari
- first_name: Mathew
  full_name: Schofield, Mathew
  last_name: Schofield
- first_name: Sara
  full_name: Seager, Sara
  last_name: Seager
- first_name: Barry
  full_name: Smalley, Barry
  last_name: Smalley
- first_name: Dennis
  full_name: Stello, Dennis
  last_name: Stello
- first_name: Róbert
  full_name: Szabó, Róbert
  last_name: Szabó
- first_name: Jamie
  full_name: Tayar, Jamie
  last_name: Tayar
- first_name: Nathalie
  full_name: Themeßl, Nathalie
  last_name: Themeßl
- first_name: Alexandra E. L.
  full_name: Thomas, Alexandra E. L.
  last_name: Thomas
- first_name: Roland K.
  full_name: Vanderspek, Roland K.
  last_name: Vanderspek
- first_name: Walter E.
  full_name: van Rossem, Walter E.
  last_name: van Rossem
- first_name: Mathieu
  full_name: Vrard, Mathieu
  last_name: Vrard
- first_name: Achim
  full_name: Weiss, Achim
  last_name: Weiss
- first_name: Timothy R.
  full_name: White, Timothy R.
  last_name: White
- first_name: Joshua N.
  full_name: Winn, Joshua N.
  last_name: Winn
- first_name: Mutlu
  full_name: Yıldız, Mutlu
  last_name: Yıldız
citation:
  ama: Chaplin WJ, Serenelli AM, Miglio A, et al. Age dating of an early Milky Way
    merger via asteroseismology of the naked-eye star ν Indi. <i>Nature Astronomy</i>.
    2020;4(4):382-389. doi:<a href="https://doi.org/10.1038/s41550-019-0975-9">10.1038/s41550-019-0975-9</a>
  apa: Chaplin, W. J., Serenelli, A. M., Miglio, A., Morel, T., Mackereth, J. T.,
    Vincenzo, F., … Yıldız, M. (2020). Age dating of an early Milky Way merger via
    asteroseismology of the naked-eye star ν Indi. <i>Nature Astronomy</i>. Springer
    Nature. <a href="https://doi.org/10.1038/s41550-019-0975-9">https://doi.org/10.1038/s41550-019-0975-9</a>
  chicago: Chaplin, William J., Aldo M. Serenelli, Andrea Miglio, Thierry Morel, J.
    Ted Mackereth, Fiorenzo Vincenzo, Hans Kjeldsen, et al. “Age Dating of an Early
    Milky Way Merger via Asteroseismology of the Naked-Eye Star ν Indi.” <i>Nature
    Astronomy</i>. Springer Nature, 2020. <a href="https://doi.org/10.1038/s41550-019-0975-9">https://doi.org/10.1038/s41550-019-0975-9</a>.
  ieee: W. J. Chaplin <i>et al.</i>, “Age dating of an early Milky Way merger via
    asteroseismology of the naked-eye star ν Indi,” <i>Nature Astronomy</i>, vol.
    4, no. 4. Springer Nature, pp. 382–389, 2020.
  ista: Chaplin WJ, Serenelli AM, Miglio A, Morel T, Mackereth JT, Vincenzo F, Kjeldsen
    H, Basu S, Ball WH, Stokholm A, Verma K, Mosumgaard JR, Silva Aguirre V, Mazumdar
    A, Ranadive P, Antia HM, Lebreton Y, Ong J, Appourchaux T, Bedding TR, Christensen-Dalsgaard
    J, Creevey O, García RA, Handberg R, Huber D, Kawaler SD, Lund MN, Metcalfe TS,
    Stassun KG, Bazot M, Beck PG, Bell KJ, Bergemann M, Buzasi DL, Benomar O, Bossini
    D, Bugnet LA, Campante TL, Orhan ZÇ, Corsaro E, González-Cuesta L, Davies GR,
    Di Mauro MP, Egeland R, Elsworth YP, Gaulme P, Ghasemi H, Guo Z, Hall OJ, Hasanzadeh
    A, Hekker S, Howe R, Jenkins JM, Jiménez A, Kiefer R, Kuszlewicz JS, Kallinger
    T, Latham DW, Lundkvist MS, Mathur S, Montalbán J, Mosser B, Bedón AM, Nielsen
    MB, Örtel S, Rendle BM, Ricker GR, Rodrigues TS, Roxburgh IW, Safari H, Schofield
    M, Seager S, Smalley B, Stello D, Szabó R, Tayar J, Themeßl N, Thomas AEL, Vanderspek
    RK, van Rossem WE, Vrard M, Weiss A, White TR, Winn JN, Yıldız M. 2020. Age dating
    of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi.
    Nature Astronomy. 4(4), 382–389.
  mla: Chaplin, William J., et al. “Age Dating of an Early Milky Way Merger via Asteroseismology
    of the Naked-Eye Star ν Indi.” <i>Nature Astronomy</i>, vol. 4, no. 4, Springer
    Nature, 2020, pp. 382–89, doi:<a href="https://doi.org/10.1038/s41550-019-0975-9">10.1038/s41550-019-0975-9</a>.
  short: W.J. Chaplin, A.M. Serenelli, A. Miglio, T. Morel, J.T. Mackereth, F. Vincenzo,
    H. Kjeldsen, S. Basu, W.H. Ball, A. Stokholm, K. Verma, J.R. Mosumgaard, V. Silva
    Aguirre, A. Mazumdar, P. Ranadive, H.M. Antia, Y. Lebreton, J. Ong, T. Appourchaux,
    T.R. Bedding, J. Christensen-Dalsgaard, O. Creevey, R.A. García, R. Handberg,
    D. Huber, S.D. Kawaler, M.N. Lund, T.S. Metcalfe, K.G. Stassun, M. Bazot, P.G.
    Beck, K.J. Bell, M. Bergemann, D.L. Buzasi, O. Benomar, D. Bossini, L.A. Bugnet,
    T.L. Campante, Z.Ç. Orhan, E. Corsaro, L. González-Cuesta, G.R. Davies, M.P. Di
    Mauro, R. Egeland, Y.P. Elsworth, P. Gaulme, H. Ghasemi, Z. Guo, O.J. Hall, A.
    Hasanzadeh, S. Hekker, R. Howe, J.M. Jenkins, A. Jiménez, R. Kiefer, J.S. Kuszlewicz,
    T. Kallinger, D.W. Latham, M.S. Lundkvist, S. Mathur, J. Montalbán, B. Mosser,
    A.M. Bedón, M.B. Nielsen, S. Örtel, B.M. Rendle, G.R. Ricker, T.S. Rodrigues,
    I.W. Roxburgh, H. Safari, M. Schofield, S. Seager, B. Smalley, D. Stello, R. Szabó,
    J. Tayar, N. Themeßl, A.E.L. Thomas, R.K. Vanderspek, W.E. van Rossem, M. Vrard,
    A. Weiss, T.R. White, J.N. Winn, M. Yıldız, Nature Astronomy 4 (2020) 382–389.
date_created: 2022-07-18T13:36:19Z
date_published: 2020-04-01T00:00:00Z
date_updated: 2022-08-22T07:08:29Z
day: '01'
doi: 10.1038/s41550-019-0975-9
extern: '1'
external_id:
  arxiv:
  - '2001.04653'
intvolume: '         4'
issue: '4'
keyword:
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2001.04653
month: '04'
oa: 1
oa_version: Preprint
page: 382-389
publication: Nature Astronomy
publication_identifier:
  eissn:
  - 2397-3366
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Age dating of an early Milky Way merger via asteroseismology of the naked-eye
  star ν Indi
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 4
year: '2020'
...
---
_id: '11612'
abstract:
- lang: eng
  text: Since the onset of the "space revolution" of high-precision high-cadence photometry,
    asteroseismology has been demonstrated as a powerful tool for informing Galactic
    archeology investigations. The launch of the NASA Transiting Exoplanet Survey
    Satellite (TESS) mission has enabled seismic-based inferences to go full sky—providing
    a clear advantage for large ensemble studies of the different Milky Way components.
    Here we demonstrate its potential for investigating the Galaxy by carrying out
    the first asteroseismic ensemble study of red giant stars observed by TESS. We
    use a sample of 25 stars for which we measure their global asteroseimic observables
    and estimate their fundamental stellar properties, such as radius, mass, and age.
    Significant improvements are seen in the uncertainties of our estimates when combining
    seismic observables from TESS with astrometric measurements from the Gaia mission
    compared to when the seismology and astrometry are applied separately. Specifically,
    when combined we show that stellar radii can be determined to a precision of a
    few percent, masses to 5%–10%, and ages to the 20% level. This is comparable to
    the precision typically obtained using end-of-mission Kepler data.
acknowledgement: 'This Letter includes data collected by the TESS mission, which are
  publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding
  for the TESS mission is provided by NASA''s Science Mission directorate. Funding
  for the TESS Asteroseismic Science Operations Centre is provided by the Danish National
  Research Foundation (grant agreement No. DNRF106), ESA PRODEX (PEA 4000119301),
  and Stellar Astrophysics Centre (SAC) at Aarhus University. V.S.A. acknowledges
  support from the Independent Research Fund Denmark (Research grant 7027-00096B).
  D.B. is supported in the form of work contract FCT/MCTES through national funds
  and by FEDER through COMPETE2020 in connection to these grants: UID/FIS/04434/2019;
  PTDC/FIS-AST/30389/2017 & POCI-01-0145-FEDER-030389. L.B., R.A.G., and B.M. acknowledge
  the support from the CNES/PLATO grant. D.B. acknowledges NASA grant NNX16AB76G.
  T.L.C. acknowledges support from the European Union''s Horizon 2020 research and
  innovation programme under the Marie Skłodowska-Curie grant agreement No. 792848
  (PULSATION). This work was supported by FCT/MCTES through national funds (UID/FIS/04434/2019).
  E.C. is funded by the European Union''s Horizon 2020 research and innovation program
  under the Marie Skłodowska-Curie grant agreement No. 664931. R.H. and M.N.L. acknowledge
  the support of the ESA PRODEX programme. T.S.R. acknowledges financial support from
  Premiale 2015 MITiC (PI B. Garilli). K.J.B. is supported by the National Science
  Foundation under Award AST-1903828. M.S.L. is supported by the Carlsberg Foundation
  (grant agreement No. CF17-0760). M.C. is funded by FCT//MCTES through national funds
  and by FEDER through COMPETE2020 through these grants: UID/FIS/04434/2019, PTDC/FIS-AST/30389/2017
  & POCI-01-0145-FEDER-030389, CEECIND/02619/2017. The research leading to the presented
  results has received funding from the European Research Council under the European
  Community''s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no
  338251 (StellarAges). A.M. acknowledges support from the European Research Council
  Consolidator Grant funding scheme (project ASTEROCHRONOMETRY, grant agreement No.
  772293, http://www.asterochronometry.eu). A.M.S. is partially supported by MINECO
  grant ESP2017-82674-R. J.C.S. acknowledges funding support from Spanish public funds
  for research under projects ESP2017-87676-2-2, and from project RYC-2012-09913 under
  the ''Ramón y Cajal'' program of the Spanish Ministry of Science and Education.
  Resources supporting this work were provided by the NASA High-End Computing (HEC)
  Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research
  Center for the production of the SPOC data products.'
article_number: L34
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Víctor Silva
  full_name: Aguirre, Víctor Silva
  last_name: Aguirre
- first_name: Dennis
  full_name: Stello, Dennis
  last_name: Stello
- first_name: Amalie
  full_name: Stokholm, Amalie
  last_name: Stokholm
- first_name: Jakob R.
  full_name: Mosumgaard, Jakob R.
  last_name: Mosumgaard
- first_name: Warrick H.
  full_name: Ball, Warrick H.
  last_name: Ball
- first_name: Sarbani
  full_name: Basu, Sarbani
  last_name: Basu
- first_name: Diego
  full_name: Bossini, Diego
  last_name: Bossini
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Derek
  full_name: Buzasi, Derek
  last_name: Buzasi
- first_name: Tiago L.
  full_name: Campante, Tiago L.
  last_name: Campante
- first_name: Lindsey
  full_name: Carboneau, Lindsey
  last_name: Carboneau
- first_name: William J.
  full_name: Chaplin, William J.
  last_name: Chaplin
- first_name: Enrico
  full_name: Corsaro, Enrico
  last_name: Corsaro
- first_name: Guy R.
  full_name: Davies, Guy R.
  last_name: Davies
- first_name: Yvonne
  full_name: Elsworth, Yvonne
  last_name: Elsworth
- first_name: Rafael A.
  full_name: García, Rafael A.
  last_name: García
- first_name: Patrick
  full_name: Gaulme, Patrick
  last_name: Gaulme
- first_name: Oliver J.
  full_name: Hall, Oliver J.
  last_name: Hall
- first_name: Rasmus
  full_name: Handberg, Rasmus
  last_name: Handberg
- first_name: Marc
  full_name: Hon, Marc
  last_name: Hon
- first_name: Thomas
  full_name: Kallinger, Thomas
  last_name: Kallinger
- first_name: Liu
  full_name: Kang, Liu
  last_name: Kang
- first_name: Mikkel N.
  full_name: Lund, Mikkel N.
  last_name: Lund
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Alexey
  full_name: Mints, Alexey
  last_name: Mints
- first_name: Benoit
  full_name: Mosser, Benoit
  last_name: Mosser
- first_name: Zeynep
  full_name: Çelik Orhan, Zeynep
  last_name: Çelik Orhan
- first_name: Thaíse S.
  full_name: Rodrigues, Thaíse S.
  last_name: Rodrigues
- first_name: Mathieu
  full_name: Vrard, Mathieu
  last_name: Vrard
- first_name: Mutlu
  full_name: Yıldız, Mutlu
  last_name: Yıldız
- first_name: Joel C.
  full_name: Zinn, Joel C.
  last_name: Zinn
- first_name: Sibel
  full_name: Örtel, Sibel
  last_name: Örtel
- first_name: Paul G.
  full_name: Beck, Paul G.
  last_name: Beck
- first_name: Keaton J.
  full_name: Bell, Keaton J.
  last_name: Bell
- first_name: Zhao
  full_name: Guo, Zhao
  last_name: Guo
- first_name: Chen
  full_name: Jiang, Chen
  last_name: Jiang
- first_name: James S.
  full_name: Kuszlewicz, James S.
  last_name: Kuszlewicz
- first_name: Charles A.
  full_name: Kuehn, Charles A.
  last_name: Kuehn
- first_name: Tanda
  full_name: Li, Tanda
  last_name: Li
- first_name: Mia S.
  full_name: Lundkvist, Mia S.
  last_name: Lundkvist
- first_name: Marc
  full_name: Pinsonneault, Marc
  last_name: Pinsonneault
- first_name: Jamie
  full_name: Tayar, Jamie
  last_name: Tayar
- first_name: Margarida S.
  full_name: Cunha, Margarida S.
  last_name: Cunha
- first_name: Saskia
  full_name: Hekker, Saskia
  last_name: Hekker
- first_name: Daniel
  full_name: Huber, Daniel
  last_name: Huber
- first_name: Andrea
  full_name: Miglio, Andrea
  last_name: Miglio
- first_name: Mario J. P.
  full_name: F. G. Monteiro, Mario J. P.
  last_name: F. G. Monteiro
- first_name: Ditte
  full_name: Slumstrup, Ditte
  last_name: Slumstrup
- first_name: Mark L.
  full_name: Winther, Mark L.
  last_name: Winther
- first_name: George
  full_name: Angelou, George
  last_name: Angelou
- first_name: Othman
  full_name: Benomar, Othman
  last_name: Benomar
- first_name: Attila
  full_name: Bódi, Attila
  last_name: Bódi
- first_name: Bruno L.
  full_name: De Moura, Bruno L.
  last_name: De Moura
- first_name: Sébastien
  full_name: Deheuvels, Sébastien
  last_name: Deheuvels
- first_name: Aliz
  full_name: Derekas, Aliz
  last_name: Derekas
- first_name: Maria Pia
  full_name: Di Mauro, Maria Pia
  last_name: Di Mauro
- first_name: Marc-Antoine
  full_name: Dupret, Marc-Antoine
  last_name: Dupret
- first_name: Antonio
  full_name: Jiménez, Antonio
  last_name: Jiménez
- first_name: Yveline
  full_name: Lebreton, Yveline
  last_name: Lebreton
- first_name: Jaymie
  full_name: Matthews, Jaymie
  last_name: Matthews
- first_name: Nicolas
  full_name: Nardetto, Nicolas
  last_name: Nardetto
- first_name: Jose D.
  full_name: do Nascimento, Jose D.
  last_name: do Nascimento
- first_name: Filipe
  full_name: Pereira, Filipe
  last_name: Pereira
- first_name: Luisa F.
  full_name: Rodríguez Díaz, Luisa F.
  last_name: Rodríguez Díaz
- first_name: Aldo M.
  full_name: Serenelli, Aldo M.
  last_name: Serenelli
- first_name: Emanuele
  full_name: Spitoni, Emanuele
  last_name: Spitoni
- first_name: Edita
  full_name: Stonkutė, Edita
  last_name: Stonkutė
- first_name: Juan Carlos
  full_name: Suárez, Juan Carlos
  last_name: Suárez
- first_name: Robert
  full_name: Szabó, Robert
  last_name: Szabó
- first_name: Vincent
  full_name: Van Eylen, Vincent
  last_name: Van Eylen
- first_name: Rita
  full_name: Ventura, Rita
  last_name: Ventura
- first_name: Kuldeep
  full_name: Verma, Kuldeep
  last_name: Verma
- first_name: Achim
  full_name: Weiss, Achim
  last_name: Weiss
- first_name: Tao
  full_name: Wu, Tao
  last_name: Wu
- first_name: Thomas
  full_name: Barclay, Thomas
  last_name: Barclay
- first_name: Jørgen
  full_name: Christensen-Dalsgaard, Jørgen
  last_name: Christensen-Dalsgaard
- first_name: Jon M.
  full_name: Jenkins, Jon M.
  last_name: Jenkins
- first_name: Hans
  full_name: Kjeldsen, Hans
  last_name: Kjeldsen
- first_name: George R.
  full_name: Ricker, George R.
  last_name: Ricker
- first_name: Sara
  full_name: Seager, Sara
  last_name: Seager
- first_name: Roland
  full_name: Vanderspek, Roland
  last_name: Vanderspek
citation:
  ama: 'Aguirre VS, Stello D, Stokholm A, et al. Detection and characterization of
    oscillating red giants: First results from the TESS satellite. <i>The Astrophysical
    Journal Letters</i>. 2020;889(2). doi:<a href="https://doi.org/10.3847/2041-8213/ab6443">10.3847/2041-8213/ab6443</a>'
  apa: 'Aguirre, V. S., Stello, D., Stokholm, A., Mosumgaard, J. R., Ball, W. H.,
    Basu, S., … Vanderspek, R. (2020). Detection and characterization of oscillating
    red giants: First results from the TESS satellite. <i>The Astrophysical Journal
    Letters</i>. IOP Publishing. <a href="https://doi.org/10.3847/2041-8213/ab6443">https://doi.org/10.3847/2041-8213/ab6443</a>'
  chicago: 'Aguirre, Víctor Silva, Dennis Stello, Amalie Stokholm, Jakob R. Mosumgaard,
    Warrick H. Ball, Sarbani Basu, Diego Bossini, et al. “Detection and Characterization
    of Oscillating Red Giants: First Results from the TESS Satellite.” <i>The Astrophysical
    Journal Letters</i>. IOP Publishing, 2020. <a href="https://doi.org/10.3847/2041-8213/ab6443">https://doi.org/10.3847/2041-8213/ab6443</a>.'
  ieee: 'V. S. Aguirre <i>et al.</i>, “Detection and characterization of oscillating
    red giants: First results from the TESS satellite,” <i>The Astrophysical Journal
    Letters</i>, vol. 889, no. 2. IOP Publishing, 2020.'
  ista: 'Aguirre VS, Stello D, Stokholm A, Mosumgaard JR, Ball WH, Basu S, Bossini
    D, Bugnet LA, Buzasi D, Campante TL, Carboneau L, Chaplin WJ, Corsaro E, Davies
    GR, Elsworth Y, García RA, Gaulme P, Hall OJ, Handberg R, Hon M, Kallinger T,
    Kang L, Lund MN, Mathur S, Mints A, Mosser B, Çelik Orhan Z, Rodrigues TS, Vrard
    M, Yıldız M, Zinn JC, Örtel S, Beck PG, Bell KJ, Guo Z, Jiang C, Kuszlewicz JS,
    Kuehn CA, Li T, Lundkvist MS, Pinsonneault M, Tayar J, Cunha MS, Hekker S, Huber
    D, Miglio A, F. G. Monteiro MJP, Slumstrup D, Winther ML, Angelou G, Benomar O,
    Bódi A, De Moura BL, Deheuvels S, Derekas A, Di Mauro MP, Dupret M-A, Jiménez
    A, Lebreton Y, Matthews J, Nardetto N, do Nascimento JD, Pereira F, Rodríguez
    Díaz LF, Serenelli AM, Spitoni E, Stonkutė E, Suárez JC, Szabó R, Van Eylen V,
    Ventura R, Verma K, Weiss A, Wu T, Barclay T, Christensen-Dalsgaard J, Jenkins
    JM, Kjeldsen H, Ricker GR, Seager S, Vanderspek R. 2020. Detection and characterization
    of oscillating red giants: First results from the TESS satellite. The Astrophysical
    Journal Letters. 889(2), L34.'
  mla: 'Aguirre, Víctor Silva, et al. “Detection and Characterization of Oscillating
    Red Giants: First Results from the TESS Satellite.” <i>The Astrophysical Journal
    Letters</i>, vol. 889, no. 2, L34, IOP Publishing, 2020, doi:<a href="https://doi.org/10.3847/2041-8213/ab6443">10.3847/2041-8213/ab6443</a>.'
  short: V.S. Aguirre, D. Stello, A. Stokholm, J.R. Mosumgaard, W.H. Ball, S. Basu,
    D. Bossini, L.A. Bugnet, D. Buzasi, T.L. Campante, L. Carboneau, W.J. Chaplin,
    E. Corsaro, G.R. Davies, Y. Elsworth, R.A. García, P. Gaulme, O.J. Hall, R. Handberg,
    M. Hon, T. Kallinger, L. Kang, M.N. Lund, S. Mathur, A. Mints, B. Mosser, Z. Çelik
    Orhan, T.S. Rodrigues, M. Vrard, M. Yıldız, J.C. Zinn, S. Örtel, P.G. Beck, K.J.
    Bell, Z. Guo, C. Jiang, J.S. Kuszlewicz, C.A. Kuehn, T. Li, M.S. Lundkvist, M.
    Pinsonneault, J. Tayar, M.S. Cunha, S. Hekker, D. Huber, A. Miglio, M.J.P. F.
    G. Monteiro, D. Slumstrup, M.L. Winther, G. Angelou, O. Benomar, A. Bódi, B.L.
    De Moura, S. Deheuvels, A. Derekas, M.P. Di Mauro, M.-A. Dupret, A. Jiménez, Y.
    Lebreton, J. Matthews, N. Nardetto, J.D. do Nascimento, F. Pereira, L.F. Rodríguez
    Díaz, A.M. Serenelli, E. Spitoni, E. Stonkutė, J.C. Suárez, R. Szabó, V. Van Eylen,
    R. Ventura, K. Verma, A. Weiss, T. Wu, T. Barclay, J. Christensen-Dalsgaard, J.M.
    Jenkins, H. Kjeldsen, G.R. Ricker, S. Seager, R. Vanderspek, The Astrophysical
    Journal Letters 889 (2020).
date_created: 2022-07-18T13:52:54Z
date_published: 2020-02-01T00:00:00Z
date_updated: 2022-08-22T07:25:51Z
day: '01'
doi: 10.3847/2041-8213/ab6443
extern: '1'
external_id:
  arxiv:
  - '1912.07604'
intvolume: '       889'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1912.07604
month: '02'
oa: 1
oa_version: Preprint
publication: The Astrophysical Journal Letters
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Detection and characterization of oscillating red giants: First results from
  the TESS satellite'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 889
year: '2020'
...
---
_id: '11622'
abstract:
- lang: eng
  text: 'The recent discovery of low-amplitude dipolar oscillation mixed modes in
    massive red giants indicates the presence of a missing physical process inside
    their cores. Stars more massive than ∼ 1.3 M⊙ are known to develop a convective
    core during the main-sequence: the dynamo process triggered by this convection
    could be the origin of a strong magnetic field inside the core of the star, trapped
    when it becomes stably stratified and for the rest of its evolution. The presence
    of highly magnetized white dwarfs strengthens the hypothesis of buried fossil
    magnetic fields inside the core of evolved low-mass stars. If such a fossil field
    exists, it should affect the mixed modes of red giants as they are sensitive to
    processes affecting the deepest layers of these stars. The impact of a magnetic
    field on dipolar oscillations modes was one of Pr. Michael J. Thompson’s research
    topics during the 90s when preparing the helioseismic SoHO space mission. As the
    detection of gravity modes in the Sun is still controversial, the investigation
    of the solar oscillation modes did not provide any hint of the existence of a
    magnetic field in the solar radiative core. Today we have access to the core of
    evolved stars thanks to the asteroseismic observation of mixed modes from CoRoT,
    Kepler, K2 and TESS missions. The idea of applying and generalizing the work done
    for the Sun came from discussions with Pr. Michael Thompson in early 2018 before
    we lost him. Following the path we drew together, we theoretically investigate
    the effect of a stable axisymmetric mixed poloidal and toroidal magnetic field,
    aligned with the rotation axis of the star, on the mixed modes frequencies of
    a typical evolved low-mass star. This enables us to estimate the magnetic perturbations
    to the eigenfrequencies of mixed dipolar modes, depending on the magnetic field
    strength and the evolutionary state of the star. We conclude that strong magnetic
    fields of ∼ 1MG should perturb the mixed-mode frequency pattern enough for its
    effects to be detectable inside current asteroseismic data.'
acknowledgement: The authors of this work acknowledge the support received from the
  PLATO CNES grant, the National Aeronautics and Space Administration under Grant
  NNX15AF13G, by the National Science Foundation grant AST-1411685, the Ramon y Cajal
  fellowship number RYC-2015-17697, the ERC SPIRE grant (647383), and the Fundation
  L’Oréal-Unesco-Académie des sciences.
alternative_title:
- Astrophysics and Space Science Proceedings
article_processing_charge: No
arxiv: 1
author:
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: V.
  full_name: Prat, V.
  last_name: Prat
- first_name: S.
  full_name: Mathis, S.
  last_name: Mathis
- first_name: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: K.
  full_name: Augustson, K.
  last_name: Augustson
- first_name: C.
  full_name: Neiner, C.
  last_name: Neiner
- first_name: M. J.
  full_name: Thompson, M. J.
  last_name: Thompson
citation:
  ama: 'Bugnet LA, Prat V, Mathis S, et al. The impact of a fossil magnetic field
    on dipolar mixed-mode frequencies in sub- and red-giant stars. In: Monteiro M,
    Garcia RA, Christensen-Dalsgaard J, McIntosh SW, eds. <i>Dynamics of the Sun and
    Stars</i>. Vol 57. 1st ed. ASSSP. Cham: Springer Nature; 2020:251-257. doi:<a
    href="https://doi.org/10.1007/978-3-030-55336-4_33">10.1007/978-3-030-55336-4_33</a>'
  apa: 'Bugnet, L. A., Prat, V., Mathis, S., García, R. A., Mathur, S., Augustson,
    K., … Thompson, M. J. (2020). The impact of a fossil magnetic field on dipolar
    mixed-mode frequencies in sub- and red-giant stars. In M. Monteiro, R. A. Garcia,
    J. Christensen-Dalsgaard, &#38; S. W. McIntosh (Eds.), <i>Dynamics of the Sun
    and Stars</i> (1st ed., Vol. 57, pp. 251–257). Cham: Springer Nature. <a href="https://doi.org/10.1007/978-3-030-55336-4_33">https://doi.org/10.1007/978-3-030-55336-4_33</a>'
  chicago: 'Bugnet, Lisa Annabelle, V. Prat, S. Mathis, R. A. García, S. Mathur, K.
    Augustson, C. Neiner, and M. J. Thompson. “The Impact of a Fossil Magnetic Field
    on Dipolar Mixed-Mode Frequencies in Sub- and Red-Giant Stars.” In <i>Dynamics
    of the Sun and Stars</i>, edited by Mario Monteiro, Rafael A Garcia, Jorgen Christensen-Dalsgaard,
    and Scott W McIntosh, 1st ed., 57:251–57. ASSSP. Cham: Springer Nature, 2020.
    <a href="https://doi.org/10.1007/978-3-030-55336-4_33">https://doi.org/10.1007/978-3-030-55336-4_33</a>.'
  ieee: 'L. A. Bugnet <i>et al.</i>, “The impact of a fossil magnetic field on dipolar
    mixed-mode frequencies in sub- and red-giant stars,” in <i>Dynamics of the Sun
    and Stars</i>, 1st ed., vol. 57, M. Monteiro, R. A. Garcia, J. Christensen-Dalsgaard,
    and S. W. McIntosh, Eds. Cham: Springer Nature, 2020, pp. 251–257.'
  ista: 'Bugnet LA, Prat V, Mathis S, García RA, Mathur S, Augustson K, Neiner C,
    Thompson MJ. 2020.The impact of a fossil magnetic field on dipolar mixed-mode
    frequencies in sub- and red-giant stars. In: Dynamics of the Sun and Stars. Astrophysics
    and Space Science Proceedings, vol. 57, 251–257.'
  mla: Bugnet, Lisa Annabelle, et al. “The Impact of a Fossil Magnetic Field on Dipolar
    Mixed-Mode Frequencies in Sub- and Red-Giant Stars.” <i>Dynamics of the Sun and
    Stars</i>, edited by Mario Monteiro et al., 1st ed., vol. 57, Springer Nature,
    2020, pp. 251–57, doi:<a href="https://doi.org/10.1007/978-3-030-55336-4_33">10.1007/978-3-030-55336-4_33</a>.
  short: L.A. Bugnet, V. Prat, S. Mathis, R.A. García, S. Mathur, K. Augustson, C.
    Neiner, M.J. Thompson, in:, M. Monteiro, R.A. Garcia, J. Christensen-Dalsgaard,
    S.W. McIntosh (Eds.), Dynamics of the Sun and Stars, 1st ed., Springer Nature,
    Cham, 2020, pp. 251–257.
date_created: 2022-07-19T08:25:41Z
date_published: 2020-12-19T00:00:00Z
date_updated: 2022-08-22T08:07:42Z
day: '19'
doi: 10.1007/978-3-030-55336-4_33
edition: '1'
editor:
- first_name: Mario
  full_name: Monteiro, Mario
  last_name: Monteiro
- first_name: Rafael A
  full_name: Garcia, Rafael A
  last_name: Garcia
- first_name: Jorgen
  full_name: Christensen-Dalsgaard, Jorgen
  last_name: Christensen-Dalsgaard
- first_name: Scott W
  full_name: McIntosh, Scott W
  last_name: McIntosh
extern: '1'
external_id:
  arxiv:
  - '2012.08684'
intvolume: '        57'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2012.08684
month: '12'
oa: 1
oa_version: Preprint
page: 251-257
place: Cham
publication: Dynamics of the Sun and Stars
publication_identifier:
  eisbn:
  - 978-3-030-55336-4
  eissn:
  - 1570-6605
  isbn:
  - 978-3-030-55335-7
  issn:
  - 1570-6591
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
series_title: ASSSP
status: public
title: The impact of a fossil magnetic field on dipolar mixed-mode frequencies in
  sub- and red-giant stars
type: book_chapter
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 57
year: '2020'
...
---
_id: '11613'
abstract:
- lang: eng
  text: Over 2,000 stars were observed for 1 month with a high enough cadence in order
    to look for acoustic modes during the survey phase of the Kepler mission. Solar-like
    oscillations have been detected in about 540 stars. The question of why no oscillations
    were detected in the remaining stars is still open. Previous works explained the
    non-detection of modes with the high level of magnetic activity of the stars.
    However, the sample of stars studied contained some classical pulsators and red
    giants that could have biased the results. In this work, we revisit this analysis
    on a cleaner sample of main-sequence solar-like stars that consists of 1,014 stars.
    First we compute the predicted amplitude of the modes of that sample and for the
    stars with detected oscillation and compare it to the noise at high frequency
    in the power spectrum. We find that the stars with detected modes have an amplitude
    to noise ratio larger than 0.94. We measure reliable rotation periods and the
    associated photometric magnetic index for 684 stars out of the full sample and
    in particular for 323 stars where the amplitude of the modes is predicted to be
    high enough to be detected. We find that among these 323 stars 32% of them have
    a level of magnetic activity larger than the Sun during its maximum activity,
    explaining the non-detection of acoustic modes. Interestingly, magnetic activity
    cannot be the primary reason responsible for the absence of detectable modes in
    the remaining 68% of the stars without acoustic modes detected and with reliable
    rotation periods. Thus, we investigate metallicity, inclination angle of the rotation
    axis, and binarity as possible causes of low mode amplitudes. Using spectroscopic
    observations for a subsample, we find that a low metallicity could be the reason
    for suppressed modes. No clear correlation with binarity nor inclination is found.
    We also derive the lower limit for our photometric activity index (of 20–30 ppm)
    below which rotation and magnetic activity are not detected. Finally, with our
    analysis we conclude that stars with a photometric activity index larger than
    2,000 ppm have 98.3% probability of not having oscillations detected.
acknowledgement: This paper includes data collected by the Kepler mission. Funding
  for the Kepler mission is provided by the NASA Science Mission directorate. Some
  of the data presented in this paper were obtained from the Mikulski Archive for
  Space Telescopes (MAST). STScI is operated by the Association of Universities for
  Research in Astronomy, Inc., under NASA contract NAS5-26555. Partly Based on observations
  obtained with the HERMES spectrograph on the Mercator Telescope, which was supported
  by the Research Foundation—Flanders (FWO), Belgium, the Research Council of KU Leuven,
  Belgium, the Fonds National de la Recherche Scientifique (F.R.S.-FNRS), Belgium,
  the Royal Observatory of Belgium, the Observatoire de Genève, Switzerland, and the
  Thüringer Landessternwarte Tautenburg, Germany. SM acknowledges support by the National
  Aeronautics and Space Administration under Grant NNX15AF13G, by the National Science
  Foundation grant AST-1411685, and the Ramon y Cajal fellowship number RYC-2015-17697.
  RG acknowledges the support from PLATO and GOLF CNES grants. ÂS acknowledges the
  support from National Aeronautics and Space Administration under Grant NNX17AF27G.
  PB acknowledges the support of the MINECO under the fellowship program Juan de la
  Cierva Incorporacion (IJCI-2015-26034).
article_number: '46'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Rafael A.
  full_name: García, Rafael A.
  last_name: García
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: Ângela R.G.
  full_name: Santos, Ângela R.G.
  last_name: Santos
- first_name: Netsha
  full_name: Santiago, Netsha
  last_name: Santiago
- first_name: Paul G.
  full_name: Beck, Paul G.
  last_name: Beck
citation:
  ama: Mathur S, García RA, Bugnet LA, Santos ÂRG, Santiago N, Beck PG. Revisiting
    the impact of stellar magnetic activity on the detectability of solar-like oscillations
    by Kepler. <i>Frontiers in Astronomy and Space Sciences</i>. 2019;6. doi:<a href="https://doi.org/10.3389/fspas.2019.00046">10.3389/fspas.2019.00046</a>
  apa: Mathur, S., García, R. A., Bugnet, L. A., Santos, Â. R. G., Santiago, N., &#38;
    Beck, P. G. (2019). Revisiting the impact of stellar magnetic activity on the
    detectability of solar-like oscillations by Kepler. <i>Frontiers in Astronomy
    and Space Sciences</i>. Frontiers Media. <a href="https://doi.org/10.3389/fspas.2019.00046">https://doi.org/10.3389/fspas.2019.00046</a>
  chicago: Mathur, Savita, Rafael A. García, Lisa Annabelle Bugnet, Ângela R.G. Santos,
    Netsha Santiago, and Paul G. Beck. “Revisiting the Impact of Stellar Magnetic
    Activity on the Detectability of Solar-like Oscillations by Kepler.” <i>Frontiers
    in Astronomy and Space Sciences</i>. Frontiers Media, 2019. <a href="https://doi.org/10.3389/fspas.2019.00046">https://doi.org/10.3389/fspas.2019.00046</a>.
  ieee: S. Mathur, R. A. García, L. A. Bugnet, Â. R. G. Santos, N. Santiago, and P.
    G. Beck, “Revisiting the impact of stellar magnetic activity on the detectability
    of solar-like oscillations by Kepler,” <i>Frontiers in Astronomy and Space Sciences</i>,
    vol. 6. Frontiers Media, 2019.
  ista: Mathur S, García RA, Bugnet LA, Santos ÂRG, Santiago N, Beck PG. 2019. Revisiting
    the impact of stellar magnetic activity on the detectability of solar-like oscillations
    by Kepler. Frontiers in Astronomy and Space Sciences. 6, 46.
  mla: Mathur, Savita, et al. “Revisiting the Impact of Stellar Magnetic Activity
    on the Detectability of Solar-like Oscillations by Kepler.” <i>Frontiers in Astronomy
    and Space Sciences</i>, vol. 6, 46, Frontiers Media, 2019, doi:<a href="https://doi.org/10.3389/fspas.2019.00046">10.3389/fspas.2019.00046</a>.
  short: S. Mathur, R.A. García, L.A. Bugnet, Â.R.G. Santos, N. Santiago, P.G. Beck,
    Frontiers in Astronomy and Space Sciences 6 (2019).
date_created: 2022-07-18T14:00:36Z
date_published: 2019-07-10T00:00:00Z
date_updated: 2022-08-22T07:29:55Z
day: '10'
doi: 10.3389/fspas.2019.00046
extern: '1'
external_id:
  arxiv:
  - '1907.01415'
intvolume: '         6'
keyword:
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1907.01415
month: '07'
oa: 1
oa_version: Preprint
publication: Frontiers in Astronomy and Space Sciences
publication_identifier:
  eissn:
  - 2296-987X
publication_status: published
publisher: Frontiers Media
quality_controlled: '1'
scopus_import: '1'
status: public
title: Revisiting the impact of stellar magnetic activity on the detectability of
  solar-like oscillations by Kepler
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 6
year: '2019'
...
---
_id: '11614'
abstract:
- lang: eng
  text: The NASA Transiting Exoplanet Survey Satellite (TESS) is about to provide
    full-frame images of almost the entire sky. The amount of stellar data to be analysed
    represents hundreds of millions stars, which is several orders of magnitude more
    than the number of stars observed by the Convection, Rotation and planetary Transits
    satellite (CoRoT), and NASA Kepler and K2 missions. We aim at automatically classifying
    the newly observed stars with near real-time algorithms to better guide the subsequent
    detailed studies. In this paper, we present a classification algorithm built to
    recognise solar-like pulsators among classical pulsators. This algorithm relies
    on the global amount of power contained in the power spectral density (PSD), also
    known as the flicker in spectral power density (FliPer). Because each type of
    pulsating star has a characteristic background or pulsation pattern, the shape
    of the PSD at different frequencies can be used to characterise the type of pulsating
    star. The FliPer classifier (FliPerClass) uses different FliPer parameters along
    with the effective temperature as input parameters to feed a ML algorithm in order
    to automatically classify the pulsating stars observed by TESS. Using noisy TESS-simulated
    data from the TESS Asteroseismic Science Consortium (TASC), we classify pulsators
    with a 98% accuracy. Among them, solar-like pulsating stars are recognised with
    a 99% accuracy, which is of great interest for a further seismic analysis of these
    stars, which are like our Sun. Similar results are obtained when we trained our
    classifier and applied it to 27-day subsets of real Kepler data. FliPerClass is
    part of the large TASC classification pipeline developed by the TESS Data for
    Asteroseismology (T’DA) classification working group.
acknowledgement: We thank the enitre T’DA team for useful comments and discussions,
  in particular Andrew Tkachenko. We also acknowledge Marc Hon, Keaton Bell, and James
  Kuszlewicz for useful comments on the manuscript. L.B. and R.A.G. acknowledge the
  support from PLATO and GOLF CNES grants. S.M. acknowledges support by the Ramon
  y Cajal fellowship number RYC-2015-17697. O.J.H. and B.M.R. acknowledge the support
  of the UK Science and Technology Facilities Council (STFC). M.N.L. acknowledges
  the support of the ESA PRODEX programme (PEA 4000119301). Funding for the Stellar
  Astrophysics Centre is provided by the Danish National Research Foundation (Grant
  DNRF106).
article_number: A79
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: G. R.
  full_name: Davies, G. R.
  last_name: Davies
- first_name: O. J.
  full_name: Hall, O. J.
  last_name: Hall
- first_name: M. N.
  full_name: Lund, M. N.
  last_name: Lund
- first_name: B. M.
  full_name: Rendle, B. M.
  last_name: Rendle
citation:
  ama: 'Bugnet LA, García RA, Mathur S, et al. FliPerClass: In search of solar-like
    pulsators among TESS targets. <i>Astronomy &#38; Astrophysics</i>. 2019;624. doi:<a
    href="https://doi.org/10.1051/0004-6361/201834780">10.1051/0004-6361/201834780</a>'
  apa: 'Bugnet, L. A., García, R. A., Mathur, S., Davies, G. R., Hall, O. J., Lund,
    M. N., &#38; Rendle, B. M. (2019). FliPerClass: In search of solar-like pulsators
    among TESS targets. <i>Astronomy &#38; Astrophysics</i>. EDP Science. <a href="https://doi.org/10.1051/0004-6361/201834780">https://doi.org/10.1051/0004-6361/201834780</a>'
  chicago: 'Bugnet, Lisa Annabelle, R. A. García, S. Mathur, G. R. Davies, O. J. Hall,
    M. N. Lund, and B. M. Rendle. “FliPerClass: In Search of Solar-like Pulsators
    among TESS Targets.” <i>Astronomy &#38; Astrophysics</i>. EDP Science, 2019. <a
    href="https://doi.org/10.1051/0004-6361/201834780">https://doi.org/10.1051/0004-6361/201834780</a>.'
  ieee: 'L. A. Bugnet <i>et al.</i>, “FliPerClass: In search of solar-like pulsators
    among TESS targets,” <i>Astronomy &#38; Astrophysics</i>, vol. 624. EDP Science,
    2019.'
  ista: 'Bugnet LA, García RA, Mathur S, Davies GR, Hall OJ, Lund MN, Rendle BM. 2019.
    FliPerClass: In search of solar-like pulsators among TESS targets. Astronomy &#38;
    Astrophysics. 624, A79.'
  mla: 'Bugnet, Lisa Annabelle, et al. “FliPerClass: In Search of Solar-like Pulsators
    among TESS Targets.” <i>Astronomy &#38; Astrophysics</i>, vol. 624, A79, EDP Science,
    2019, doi:<a href="https://doi.org/10.1051/0004-6361/201834780">10.1051/0004-6361/201834780</a>.'
  short: L.A. Bugnet, R.A. García, S. Mathur, G.R. Davies, O.J. Hall, M.N. Lund, B.M.
    Rendle, Astronomy &#38; Astrophysics 624 (2019).
date_created: 2022-07-18T14:13:34Z
date_published: 2019-04-19T00:00:00Z
date_updated: 2022-08-22T07:32:51Z
day: '19'
doi: 10.1051/0004-6361/201834780
extern: '1'
external_id:
  arxiv:
  - '1902.09854'
intvolume: '       624'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1902.09854
month: '04'
oa: 1
oa_version: Preprint
publication: Astronomy & Astrophysics
publication_identifier:
  eissn:
  - 1432-0746
  issn:
  - 0004-6361
publication_status: published
publisher: EDP Science
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'FliPerClass: In search of solar-like pulsators among TESS targets'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 624
year: '2019'
...
---
_id: '11615'
abstract:
- lang: eng
  text: The recently published Kepler mission Data Release 25 (DR25) reported on ∼197 000
    targets observed during the mission. Despite this, no wide search for red giants
    showing solar-like oscillations have been made across all stars observed in Kepler’s
    long-cadence mode. In this work, we perform this task using custom apertures on
    the Kepler pixel files and detect oscillations in 21 914 stars, representing the
    largest sample of solar-like oscillating stars to date. We measure their frequency
    at maximum power, νmax, down to νmax≃4μHz and obtain log (g) estimates with a
    typical uncertainty below 0.05 dex, which is superior to typical measurements
    from spectroscopy. Additionally, the νmax distribution of our detections show
    good agreement with results from a simulated model of the Milky Way, with a ratio
    of observed to predicted stars of 0.992 for stars with 10<νmax<270μHz. Among our
    red giant detections, we find 909 to be dwarf/subgiant stars whose flux signal
    is polluted by a neighbouring giant as a result of using larger photometric apertures
    than those used by the NASA Kepler science processing pipeline. We further find
    that only 293 of the polluting giants are known Kepler targets. The remainder
    comprises over 600 newly identified oscillating red giants, with many expected
    to belong to the Galactic halo, serendipitously falling within the Kepler pixel
    files of targeted stars.
acknowledgement: Funding for this Discovery mission is provided by NASA’s Science
  mission Directorate. We thank the entire Kepler team without whom this investigation
  would not be possible. DS is the recipient of an Australian Research Council Future
  Fellowship (project number FT1400147). RAG acknowledges the support from CNES. SM
  acknowledges support from NASA grant NNX15AF13G, NSF grant AST-1411685, and the
  Ramon y Cajal fellowship number RYC-2015-17697. ILC acknowledges scholarship support
  from the University of Sydney. We would like to thank Nicholas Barbara and Timothy
  Bedding for providing us with a list of variable stars that helped to validate a
  number of detections in this study. We also thank the group at the University of
  Sydney for fruitful discussions. Finally, we gratefully acknowledge the support
  of NVIDIA Corporation with the donation of the Titan Xp GPU used for this research.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Marc
  full_name: Hon, Marc
  last_name: Hon
- first_name: Dennis
  full_name: Stello, Dennis
  last_name: Stello
- first_name: Rafael A
  full_name: García, Rafael A
  last_name: García
- first_name: Savita
  full_name: Mathur, Savita
  last_name: Mathur
- first_name: Sanjib
  full_name: Sharma, Sanjib
  last_name: Sharma
- first_name: Isabel L
  full_name: Colman, Isabel L
  last_name: Colman
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
citation:
  ama: Hon M, Stello D, García RA, et al. A search for red giant solar-like oscillations
    in all Kepler data. <i>Monthly Notices of the Royal Astronomical Society</i>.
    2019;485(4):5616-5630. doi:<a href="https://doi.org/10.1093/mnras/stz622">10.1093/mnras/stz622</a>
  apa: Hon, M., Stello, D., García, R. A., Mathur, S., Sharma, S., Colman, I. L.,
    &#38; Bugnet, L. A. (2019). A search for red giant solar-like oscillations in
    all Kepler data. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford
    University Press. <a href="https://doi.org/10.1093/mnras/stz622">https://doi.org/10.1093/mnras/stz622</a>
  chicago: Hon, Marc, Dennis Stello, Rafael A García, Savita Mathur, Sanjib Sharma,
    Isabel L Colman, and Lisa Annabelle Bugnet. “A Search for Red Giant Solar-like
    Oscillations in All Kepler Data.” <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press, 2019. <a href="https://doi.org/10.1093/mnras/stz622">https://doi.org/10.1093/mnras/stz622</a>.
  ieee: M. Hon <i>et al.</i>, “A search for red giant solar-like oscillations in all
    Kepler data,” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 485,
    no. 4. Oxford University Press, pp. 5616–5630, 2019.
  ista: Hon M, Stello D, García RA, Mathur S, Sharma S, Colman IL, Bugnet LA. 2019.
    A search for red giant solar-like oscillations in all Kepler data. Monthly Notices
    of the Royal Astronomical Society. 485(4), 5616–5630.
  mla: Hon, Marc, et al. “A Search for Red Giant Solar-like Oscillations in All Kepler
    Data.” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 485, no.
    4, Oxford University Press, 2019, pp. 5616–30, doi:<a href="https://doi.org/10.1093/mnras/stz622">10.1093/mnras/stz622</a>.
  short: M. Hon, D. Stello, R.A. García, S. Mathur, S. Sharma, I.L. Colman, L.A. Bugnet,
    Monthly Notices of the Royal Astronomical Society 485 (2019) 5616–5630.
date_created: 2022-07-18T14:26:03Z
date_published: 2019-06-01T00:00:00Z
date_updated: 2022-08-22T07:35:19Z
day: '01'
doi: 10.1093/mnras/stz622
extern: '1'
external_id:
  arxiv:
  - '1903.00115'
intvolume: '       485'
issue: '4'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- asteroseismology
- 'methods: data analysis'
- 'techniques: image processing'
- 'stars: oscillations'
- 'stars: statistics'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1903.00115
month: '06'
oa: 1
oa_version: Preprint
page: 5616-5630
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  eissn:
  - 1365-2966
  issn:
  - 0035-8711
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: A search for red giant solar-like oscillations in all Kepler data
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 485
year: '2019'
...
