---
_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. The Astronomical Journal. 2021;162(5). doi:10.3847/1538-3881/ac166a'
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.
The Astronomical Journal. IOP Publishing. https://doi.org/10.3847/1538-3881/ac166a'
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.” The
Astronomical Journal. IOP Publishing, 2021. https://doi.org/10.3847/1538-3881/ac166a.'
ieee: 'J. Audenaert et al., “TESS Data for Asteroseismology (T’DA) stellar
variability classification pipeline: Setup and application to the Kepler Q9 data,”
The Astronomical Journal, 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.” The
Astronomical Journal, vol. 162, no. 5, 209, IOP Publishing, 2021, doi:10.3847/1538-3881/ac166a.'
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: '13459'
abstract:
- lang: eng
text: The B emission-line stars are rapid rotators that were probably spun up by
mass and angular momentum accretion through mass transfer in an interacting binary.
Mass transfer will strip the donor star of its envelope to create a small and
hot subdwarf remnant. Here we report on Hubble Space Telescope/STIS far-ultraviolet
spectroscopy of a sample of Be stars that reveals the presence of the hot sdO
companion through the calculation of cross-correlation functions of the observed
and model spectra. We clearly detect the spectral signature of the sdO star in
10 of the 13 stars in the sample, and the spectral signals indicate that the sdO
stars are hot, relatively faint, and slowly rotating as predicted by models. A
comparison of their temperatures and radii with evolutionary tracks indicates
that the sdO stars occupy the relatively long-lived, He-core burning stage. Only
1 of the 10 detections was a known binary prior to this investigation, which emphasizes
the difficulty of finding such Be+sdO binaries through optical spectroscopy. However,
these results and others indicate that many Be stars probably host hot subdwarf
companions.
article_number: '248'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Luqian
full_name: Wang, Luqian
last_name: Wang
- first_name: Douglas R.
full_name: Gies, Douglas R.
last_name: Gies
- first_name: Geraldine J.
full_name: Peters, Geraldine J.
last_name: Peters
- first_name: Ylva Louise Linsdotter
full_name: Götberg, Ylva Louise Linsdotter
id: d0648d0c-0f64-11ee-a2e0-dd0faa2e4f7d
last_name: Götberg
orcid: 0000-0002-6960-6911
- first_name: S. Drew
full_name: Chojnowski, S. Drew
last_name: Chojnowski
- first_name: Kathryn V.
full_name: Lester, Kathryn V.
last_name: Lester
- first_name: Steve B.
full_name: Howell, Steve B.
last_name: Howell
citation:
ama: Wang L, Gies DR, Peters GJ, et al. The detection and characterization of Be+sdO
binaries from HST/STIS FUV spectroscopy. The Astronomical Journal. 2021;161(5).
doi:10.3847/1538-3881/abf144
apa: Wang, L., Gies, D. R., Peters, G. J., Götberg, Y. L. L., Chojnowski, S. D.,
Lester, K. V., & Howell, S. B. (2021). The detection and characterization
of Be+sdO binaries from HST/STIS FUV spectroscopy. The Astronomical Journal.
American Astronomical Society. https://doi.org/10.3847/1538-3881/abf144
chicago: Wang, Luqian, Douglas R. Gies, Geraldine J. Peters, Ylva Louise Linsdotter
Götberg, S. Drew Chojnowski, Kathryn V. Lester, and Steve B. Howell. “The Detection
and Characterization of Be+sdO Binaries from HST/STIS FUV Spectroscopy.” The
Astronomical Journal. American Astronomical Society, 2021. https://doi.org/10.3847/1538-3881/abf144.
ieee: L. Wang et al., “The detection and characterization of Be+sdO binaries
from HST/STIS FUV spectroscopy,” The Astronomical Journal, vol. 161, no.
5. American Astronomical Society, 2021.
ista: Wang L, Gies DR, Peters GJ, Götberg YLL, Chojnowski SD, Lester KV, Howell
SB. 2021. The detection and characterization of Be+sdO binaries from HST/STIS
FUV spectroscopy. The Astronomical Journal. 161(5), 248.
mla: Wang, Luqian, et al. “The Detection and Characterization of Be+sdO Binaries
from HST/STIS FUV Spectroscopy.” The Astronomical Journal, vol. 161, no.
5, 248, American Astronomical Society, 2021, doi:10.3847/1538-3881/abf144.
short: L. Wang, D.R. Gies, G.J. Peters, Y.L.L. Götberg, S.D. Chojnowski, K.V. Lester,
S.B. Howell, The Astronomical Journal 161 (2021).
date_created: 2023-08-03T10:11:57Z
date_published: 2021-05-04T00:00:00Z
date_updated: 2023-08-21T11:35:50Z
day: '04'
doi: 10.3847/1538-3881/abf144
extern: '1'
external_id:
arxiv:
- '2103.13642'
intvolume: ' 161'
issue: '5'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2103.13642
month: '05'
oa: 1
oa_version: Preprint
publication: The Astronomical Journal
publication_identifier:
eissn:
- 1538-3881
issn:
- 0004-6256
publication_status: published
publisher: American Astronomical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: The detection and characterization of Be+sdO binaries from HST/STIS FUV spectroscopy
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 161
year: '2021'
...