---
_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: '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: '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'
...
---
_id: '11630'
abstract:
- lang: eng
  text: 'The second mission of NASA’s Kepler satellite, K2, has collected hundreds
    of thousands of lightcurves for stars close to the ecliptic plane. This new sample
    could increase the number of known pulsating stars and then improve our understanding
    of those stars. For the moment only a few stars have been properly classified
    and published. In this work, we present a method to automaticly classify K2 pulsating
    stars using a Machine Learning technique called Random Forest. The objective is
    to sort out the stars in four classes: red giant (RG), main-sequence Solar-like
    stars (SL), classical pulsators (PULS) and Other. To do this we use the effective
    temperatures and the luminosities of the stars as well as the FliPer features,
    that measures the amount of power contained in the power spectral density. The
    classifier now retrieves the right classification for more than 80% of the stars.'
article_number: '1906.09611'
article_processing_charge: No
arxiv: 1
author:
- first_name: A. Le
  full_name: Saux, A. Le
  last_name: Saux
- 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: S. N.
  full_name: Breton, S. N.
  last_name: Breton
- first_name: R. A.
  full_name: Garcia, R. A.
  last_name: Garcia
citation:
  ama: Saux AL, Bugnet LA, Mathur S, Breton SN, Garcia RA. Automatic classification
    of K2 pulsating stars using machine learning techniques. <i>arXiv</i>. doi:<a
    href="https://doi.org/10.48550/arXiv.1906.09611">10.48550/arXiv.1906.09611</a>
  apa: Saux, A. L., Bugnet, L. A., Mathur, S., Breton, S. N., &#38; Garcia, R. A.
    (n.d.). Automatic classification of K2 pulsating stars using machine learning
    techniques. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.1906.09611">https://doi.org/10.48550/arXiv.1906.09611</a>
  chicago: Saux, A. Le, Lisa Annabelle Bugnet, S. Mathur, S. N. Breton, and R. A.
    Garcia. “Automatic Classification of K2 Pulsating Stars Using Machine Learning
    Techniques.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.1906.09611">https://doi.org/10.48550/arXiv.1906.09611</a>.
  ieee: A. L. Saux, L. A. Bugnet, S. Mathur, S. N. Breton, and R. A. Garcia, “Automatic
    classification of K2 pulsating stars using machine learning techniques,” <i>arXiv</i>.
    .
  ista: Saux AL, Bugnet LA, Mathur S, Breton SN, Garcia RA. Automatic classification
    of K2 pulsating stars using machine learning techniques. arXiv, 1906.09611.
  mla: Saux, A. Le, et al. “Automatic Classification of K2 Pulsating Stars Using Machine
    Learning Techniques.” <i>ArXiv</i>, 1906.09611, doi:<a href="https://doi.org/10.48550/arXiv.1906.09611">10.48550/arXiv.1906.09611</a>.
  short: A.L. Saux, L.A. Bugnet, S. Mathur, S.N. Breton, R.A. Garcia, ArXiv (n.d.).
date_created: 2022-07-21T06:57:10Z
date_published: 2019-06-23T00:00:00Z
date_updated: 2022-08-22T08:20:29Z
day: '23'
doi: 10.48550/arXiv.1906.09611
extern: '1'
external_id:
  arxiv:
  - '1906.09611'
keyword:
- asteroseismology - methods
- data analysis - thecniques
- machine learning - stars
- oscillations
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.1906.09611
month: '06'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: submitted
status: public
title: Automatic classification of K2 pulsating stars using machine learning techniques
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2019'
...
---
_id: '11618'
abstract:
- lang: eng
  text: Asteroseismology provides global stellar parameters such as masses, radii,
    or surface gravities using mean global seismic parameters and effective temperature
    for thousands of low-mass stars (0.8 M⊙ < M < 3 M⊙). This methodology has been
    successfully applied to stars in which acoustic modes excited by turbulent convection
    are measured. Other methods such as the Flicker technique can also be used to
    determine stellar surface gravities, but only works for log g above 2.5 dex. In
    this work, we present a new metric called FliPer (Flicker in spectral power density,
    in opposition to the standard Flicker measurement which is computed in the time
    domain); it is able to extend the range for which reliable surface gravities can
    be obtained (0.1 < log g < 4.6 dex) without performing any seismic analysis for
    stars brighter than Kp < 14. FliPer takes into account the average variability
    of a star measured in the power density spectrum in a given range of frequencies.
    However, FliPer values calculated on several ranges of frequency are required
    to better characterize a star. Using a large set of asteroseismic targets it is
    possible to calibrate the behavior of surface gravity with FliPer through machine
    learning. This calibration made with a random forest regressor covers a wide range
    of surface gravities from main-sequence stars to subgiants and red giants, with
    very small uncertainties from 0.04 to 0.1 dex. FliPer values can be inserted in
    automatic global seismic pipelines to either give an estimation of the stellar
    surface gravity or to assess the quality of the seismic results by detecting any
    outliers in the obtained νmax values. FliPer also constrains the surface gravities
    of main-sequence dwarfs using only long-cadence data for which the Nyquist frequency
    is too low to measure the acoustic-mode properties.
acknowledgement: We thank the anonymous referee for the very useful comments. We would
  also like to thank M. Benbakoura for his help in analyzing the light curves of several
  binary systems included in our set of stars. L.B. and R.A.G. acknowledge the support
  from PLATO and GOLF CNES grants. S.M. acknowledges support from the National Aeronautics
  and Space Administration under Grant NNX15AF13G, the National Science Foundation
  grant AST-1411685, and the Ramon y Cajal fellowship no. RYC-2015-17697. E.C. is
  funded by the European Union’s Horizon 2020 research and innovation program under
  the Marie Sklodowska-Curie grant agreement no. 664931. O.J.H and B.M.R. acknowledge
  the support of the UK Science and Technology Facilities Council (STFC). Funding
  for the Stellar Astrophysics Centre is provided by the Danish National Research
  Foundation (Grant DNRF106). This research has made use of NASA’s Astrophysics Data
  System. 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.
article_number: A38
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: G. R.
  full_name: Davies, G. R.
  last_name: Davies
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: E.
  full_name: Corsaro, E.
  last_name: Corsaro
- first_name: O. J.
  full_name: Hall, O. J.
  last_name: Hall
- first_name: B. M.
  full_name: Rendle, B. M.
  last_name: Rendle
citation:
  ama: 'Bugnet LA, García RA, Davies GR, et al. FliPer: A global measure of power
    density to estimate surface gravities of main-sequence solar-like stars and red
    giants. <i>Astronomy &#38; Astrophysics</i>. 2018;620. doi:<a href="https://doi.org/10.1051/0004-6361/201833106">10.1051/0004-6361/201833106</a>'
  apa: 'Bugnet, L. A., García, R. A., Davies, G. R., Mathur, S., Corsaro, E., Hall,
    O. J., &#38; Rendle, B. M. (2018). FliPer: A global measure of power density to
    estimate surface gravities of main-sequence solar-like stars and red giants. <i>Astronomy
    &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/201833106">https://doi.org/10.1051/0004-6361/201833106</a>'
  chicago: 'Bugnet, Lisa Annabelle, R. A. García, G. R. Davies, S. Mathur, E. Corsaro,
    O. J. Hall, and B. M. Rendle. “FliPer: A Global Measure of Power Density to Estimate
    Surface Gravities of Main-Sequence Solar-like Stars and Red Giants.” <i>Astronomy
    &#38; Astrophysics</i>. EDP Sciences, 2018. <a href="https://doi.org/10.1051/0004-6361/201833106">https://doi.org/10.1051/0004-6361/201833106</a>.'
  ieee: 'L. A. Bugnet <i>et al.</i>, “FliPer: A global measure of power density to
    estimate surface gravities of main-sequence solar-like stars and red giants,”
    <i>Astronomy &#38; Astrophysics</i>, vol. 620. EDP Sciences, 2018.'
  ista: 'Bugnet LA, García RA, Davies GR, Mathur S, Corsaro E, Hall OJ, Rendle BM.
    2018. FliPer: A global measure of power density to estimate surface gravities
    of main-sequence solar-like stars and red giants. Astronomy &#38; Astrophysics.
    620, A38.'
  mla: 'Bugnet, Lisa Annabelle, et al. “FliPer: A Global Measure of Power Density
    to Estimate Surface Gravities of Main-Sequence Solar-like Stars and Red Giants.”
    <i>Astronomy &#38; Astrophysics</i>, vol. 620, A38, EDP Sciences, 2018, doi:<a
    href="https://doi.org/10.1051/0004-6361/201833106">10.1051/0004-6361/201833106</a>.'
  short: L.A. Bugnet, R.A. García, G.R. Davies, S. Mathur, E. Corsaro, O.J. Hall,
    B.M. Rendle, Astronomy &#38; Astrophysics 620 (2018).
date_created: 2022-07-18T14:37:39Z
date_published: 2018-12-01T00:00:00Z
date_updated: 2022-08-22T07:41:07Z
day: '01'
doi: 10.1051/0004-6361/201833106
extern: '1'
external_id:
  arxiv:
  - '1809.05105'
intvolume: '       620'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- asteroseismology / methods
- data analysis / stars
- oscillations
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1809.05105
month: '12'
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: 'FliPer: A global measure of power density to estimate surface gravities of
  main-sequence solar-like stars and red giants'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 620
year: '2018'
...
---
_id: '11631'
abstract:
- lang: eng
  text: "The recently launched NASA Transiting Exoplanet Survey Satellite (TESS) mission
    is going to collect lightcurves for a few hundred million of stars and we expect
    to increase the number of pulsating stars to analyze compared to the few thousand
    stars observed by the CoRoT, Kepler and K2 missions. However, most of the TESS
    targets have not yet been properly classified and characterized. In order to improve
    the analysis of the TESS data, it is crucial to determine the type of stellar
    pulsations in a timely manner. We propose an automatic method to classify stars
    attending to their pulsation properties, in particular, to identify solar-like
    pulsators among all TESS targets. It relies on the use of the global amount of
    power contained in the power spectrum (already known as the FliPer method) as
    a key parameter, along with\r\nthe effective temperature, to feed into a machine
    learning classifier. Our study, based on TESS simulated datasets, shows that we
    are able to classify pulsators with a 98% accuracy."
article_number: '1811.12140'
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: R. A.
  full_name: García, R. A.
  last_name: García
- first_name: G. R.
  full_name: Davies, G. R.
  last_name: Davies
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: O. J.
  full_name: Hall, O. J.
  last_name: Hall
- first_name: B. M.
  full_name: Rendle, B. M.
  last_name: Rendle
citation:
  ama: 'Bugnet LA, García RA, Davies GR, Mathur S, Hall OJ, Rendle BM. FliPer: Classifying
    TESS pulsating stars. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.1811.12140">10.48550/arXiv.1811.12140</a>'
  apa: 'Bugnet, L. A., García, R. A., Davies, G. R., Mathur, S., Hall, O. J., &#38;
    Rendle, B. M. (n.d.). FliPer: Classifying TESS pulsating stars. <i>arXiv</i>.
    <a href="https://doi.org/10.48550/arXiv.1811.12140">https://doi.org/10.48550/arXiv.1811.12140</a>'
  chicago: 'Bugnet, Lisa Annabelle, R. A. García, G. R. Davies, S. Mathur, O. J. Hall,
    and B. M. Rendle. “FliPer: Classifying TESS Pulsating Stars.” <i>ArXiv</i>, n.d.
    <a href="https://doi.org/10.48550/arXiv.1811.12140">https://doi.org/10.48550/arXiv.1811.12140</a>.'
  ieee: 'L. A. Bugnet, R. A. García, G. R. Davies, S. Mathur, O. J. Hall, and B. M.
    Rendle, “FliPer: Classifying TESS pulsating stars,” <i>arXiv</i>. .'
  ista: 'Bugnet LA, García RA, Davies GR, Mathur S, Hall OJ, Rendle BM. FliPer: Classifying
    TESS pulsating stars. arXiv, 1811.12140.'
  mla: 'Bugnet, Lisa Annabelle, et al. “FliPer: Classifying TESS Pulsating Stars.”
    <i>ArXiv</i>, 1811.12140, doi:<a href="https://doi.org/10.48550/arXiv.1811.12140">10.48550/arXiv.1811.12140</a>.'
  short: L.A. Bugnet, R.A. García, G.R. Davies, S. Mathur, O.J. Hall, B.M. Rendle,
    ArXiv (n.d.).
date_created: 2022-07-21T07:05:23Z
date_published: 2018-11-29T00:00:00Z
date_updated: 2022-08-22T08:41:55Z
day: '29'
doi: 10.48550/arXiv.1811.12140
extern: '1'
external_id:
  arxiv:
  - '1811.12140'
keyword:
- asteroseismology - methods
- data analysis - stars
- oscillations
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: ' https://doi.org/10.48550/arXiv.1811.12140'
month: '11'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: submitted
status: public
title: 'FliPer: Classifying TESS pulsating stars'
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2018'
...
---
_id: '11633'
abstract:
- lang: eng
  text: Our understanding of stars through asteroseismic data analysis is limited
    by our ability to take advantage of the huge amount of observed stars provided
    by space missions such as CoRoT, Kepler , K2, and soon TESS and PLATO. Global
    seismic pipelines provide global stellar parameters such as mass and radius using
    the mean seismic parameters, as well as the effective temperature. These pipelines
    are commonly used automatically on thousands of stars observed by K2 for 3 months
    (and soon TESS for at least ∼ 1 month). However, pipelines are not immune from
    misidentifying noise peaks and stellar oscillations. Therefore, new validation
    techniques are required to assess the quality of these results. We present a new
    metric called FliPer (Flicker in Power), which takes into account the average
    variability at all measured time scales. The proper calibration of FliPer enables
    us to obtain good estimations of global stellar parameters such as surface gravity
    that are robust against the influence of noise peaks and hence are an excellent
    way to find faults in asteroseismic pipelines.
article_number: '1711.02890'
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: R. A.
  full_name: Garcia, R. A.
  last_name: Garcia
- first_name: G. R.
  full_name: Davies, G. R.
  last_name: Davies
- first_name: S.
  full_name: Mathur, S.
  last_name: Mathur
- first_name: E.
  full_name: Corsaro, E.
  last_name: Corsaro
citation:
  ama: 'Bugnet LA, Garcia RA, Davies GR, Mathur S, Corsaro E. FliPer: Checking the
    reliability of global seismic parameters from automatic pipelines. <i>arXiv</i>.
    doi:<a href="https://doi.org/10.48550/arXiv.1711.02890">10.48550/arXiv.1711.02890</a>'
  apa: 'Bugnet, L. A., Garcia, R. A., Davies, G. R., Mathur, S., &#38; Corsaro, E.
    (n.d.). FliPer: Checking the reliability of global seismic parameters from automatic
    pipelines. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.1711.02890">https://doi.org/10.48550/arXiv.1711.02890</a>'
  chicago: 'Bugnet, Lisa Annabelle, R. A. Garcia, G. R. Davies, S. Mathur, and E.
    Corsaro. “FliPer: Checking the Reliability of Global Seismic Parameters from Automatic
    Pipelines.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.1711.02890">https://doi.org/10.48550/arXiv.1711.02890</a>.'
  ieee: 'L. A. Bugnet, R. A. Garcia, G. R. Davies, S. Mathur, and E. Corsaro, “FliPer:
    Checking the reliability of global seismic parameters from automatic pipelines,”
    <i>arXiv</i>. .'
  ista: 'Bugnet LA, Garcia RA, Davies GR, Mathur S, Corsaro E. FliPer: Checking the
    reliability of global seismic parameters from automatic pipelines. arXiv, 1711.02890.'
  mla: 'Bugnet, Lisa Annabelle, et al. “FliPer: Checking the Reliability of Global
    Seismic Parameters from Automatic Pipelines.” <i>ArXiv</i>, 1711.02890, doi:<a
    href="https://doi.org/10.48550/arXiv.1711.02890">10.48550/arXiv.1711.02890</a>.'
  short: L.A. Bugnet, R.A. Garcia, G.R. Davies, S. Mathur, E. Corsaro, ArXiv (n.d.).
date_created: 2022-07-21T07:13:13Z
date_published: 2017-11-08T00:00:00Z
date_updated: 2022-08-22T08:45:42Z
day: '08'
doi: 10.48550/arXiv.1711.02890
extern: '1'
external_id:
  arxiv:
  - '1711.02890'
keyword:
- asteroseismology - methods
- data analysis - stars
- oscillations
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.1711.02890
month: '11'
oa: 1
oa_version: Preprint
publication: arXiv
publication_status: submitted
status: public
title: 'FliPer: Checking the reliability of global seismic parameters from automatic
  pipelines'
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2017'
...