Stars: horizontal-branch; Stars: oscillations; Stars: variables: general; Subdwarfs; Exo-planets; Satellite data; Satellite mission; Short periods; Star oscillations; Stars: horizontal branch; Stars:variables:general; Stellars; Subdwarf stars; Astronomy and Astrophysics; Space and Planetary Science; astro-ph.SR
Abstract :
[en] We present results of a Transiting Exoplanet Survey Satellite (TESS) search for short-period pulsations in compact stellar objects observed in years 1 and 3 of the TESS mission, during which the southern ecliptic hemisphere was targeted. We describe the TESS data used and the details of the search method. For many of the targets, we use unpublished spectroscopic observations to classify the objects. From the TESS photometry, we clearly identify 43 short-period hot-subdwarf pulsators, including 32 sdB stars, eight sdOB stars, two sdO stars, and, significantly, one He-sdOB star, which is the first of this kind to show short-period pulsations. Eight stars show signals at both low and high frequencies, and are therefore "hybrid"pulsators.We report the list of prewhitened frequencies and we show the amplitude spectra calculated from the TESS data. We make an attempt to identify possible multiplets caused by stellar rotation, and we select four candidates with rotation periods between 1 and 12.9 days. The most interesting targets discovered in this survey should be observed throughout the remainder of the TESS mission and from the ground. Asteroseismic investigations of these data sets will be invaluable in revealing the interior structure of these stars and will boost our understanding of their evolutionary history. We find three additional new variable stars but their spectral and variability types remain to be constrained.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Baran, A.S. ; Astronomical Observatory, University of Warsaw, Warszawa, Poland ; Department of Physics Astronomy and Materials Science, Missouri State University, Springfield, United States
Van Grootel, Valérie ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Ostensen, R.H.; Department of Physics Astronomy and Materials Science, Missouri State University, Springfield, United States ; Recogito AS, Fauske, Norway
Worters, H.L.; South African Astronomical Observatory, Observatory, South Africa
Sahoo, S.K. ; Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Warsaw, Poland
Sanjayan, S.; Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Warsaw, Poland
Charpinet, S. ; IRAP, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France
Nemeth, P. ; Astronomical Institute of the Czech Academy of Sciences, Ondrejov, Czech Republic ; Astroserver.org, Malomsok, Hungary
Telting, J.H.; Nordic Optical Telescope, Breña Baja, Spain ; Department of Physics and Astronomy, Aarhus University, Aarhus C, Denmark
Kilkenny, D.; Department of Physics and Astronomy, University of the Western Cape, Bellville, South Africa
Language :
English
Title :
Short-period pulsating hot-subdwarf stars observed by TESS: I. Southern ecliptic hemisphere
We thank Don Kurtz for valuable comments, which have significantly improved the quality of the manuscript. Financial support from the National Science Centre in Poland under project No. UMO-2017/26/E/ST9/00703 is acknowledged. SC acknowledges financial support from the Centre National d’Études Spatiales (CNES, France) and from the Agence Nationale de la Recherche (ANR, France) under grant ANR-17-CE31-0018. PN acknowledges support from the Grant Agency of the Czech Republic (GAČR 22-34467S). The Astronomical Institute in Ondřejov is supported by the project RVO:67985815. This paper includes data collected with the TESS mission, obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the TESS mission is provided by the NASA Explorer Program. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5–26555. This paper uses observations made at the South African Astronomical Observatory (SAAO). This paper uses observations made at the Nordic Optical Telescope (NOT). This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. This work has also 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. V.V.G. is a F.R.S.-FNRS Research Associate. This research has used the services of https://astroserver.org/">https://astroserver.org/ .
Charpinet, S., Fontaine, G., &Brassard, P. 2003, in White Dwarfs, (NATO ASI Ser. B, 105), ed. D. de Martino, R. Silvotti, J.-E. Solheim, &R. Kalytis (Dordrecht: Kluwer), 69
Charpinet, S., Green, E. M., Baglin, A., et al. 2010, A&A, 516, L6
Christlieb, N., Wisotzki, L., Reimers, D., et al. 2001, A&A, 366, 898
Edelmann, H., Heber, U., Altmann, M., Karl, C., &Lisker, T. 2005, A&A, 442, 1023
Fontaine, G., Brassard, P., Green, E. M., et al. 2008, A&A, 486, L39
Mackebrandt, F., Schuh, S., Silvotti, R., et al. 2020, A&A, 638, A108
McCook, G. P., &Sion, E. M. 1987, ApJS, 65, 603
Menzies, J., &Marang, F. 1986, in Instrumentation and Research Programmes for Small Telescopes, eds. J. Hearnshaw, &P. Cottrell (Dordrecht: Reidel), Proceedings of the International Astronomical Union Symposium No. 118, 305
Miller Bertolami, M. M., Althaus, L. G., Unglaub, K., &Weiss, A. 2008, A&A, 491, 253
Miller Bertolami, M. M., Battich, T., Córsico, A. H., Althaus, L. G., &Wachlin, F. C. 2022, MNRAS, 511, L60
Moehler, S., de Boer, K. S., &Heber, U. 1990, A&A, 239, 265
Németh, P., Kawka, A., &Vennes, S. 2012, MNRAS, 427, 2180
O?Donoghue, D., Lynas-Gray, A. E., Kilkenny, D., Stobie, R. S., &Koen, C. 1997, MNRAS, 285, 657
O?Donoghue, D., Koen, C., Lynas-Gray, A. E., Kilkenny, D., &van Wyk, F. 1998, MNRAS, 296, 306
O?Donoghue, D., Kilkenny, D., Koen, C., et al. 2013, MNRAS, 431, 240
Oreiro, R., Østensen, R. H., Green, E. M., &Geier, S. 2009, A&A, 496, 827
Østensen, R. H. 2012, ASP Conf. Ser., 452, 233
Østensen, R. H., Oreiro, R., Solheim, J. E., et al. 2010, A&A, 513, A6
Østensen, R. H., Jeffery, C. S., Saio, H., et al. 2020, MNRAS, 499, 3738
Preece, H. P., Hamers, A. S., Battich, T., &Rajamuthukumar, A. S. 2022, MNRAS, 517, 2111
Ramsay, G., &Hakala, P. 2005, MNRAS, 360, 314
Ramsay, G., Napiwotzki, R., Hakala, P., &Lehto, H. 2006, MNRAS, 371, 957
Randall, S., van Grootel, V., Fontaine, G., Charpinet, S., &Brassard, P. 2009, A&A, 507, 911
Randall, S. K., Fontaine, G., Charpinet, S., et al. 2006, ApJ, 648, 637
Randall, S. K., Calamida, A., Fontaine, G., Bono, G., &Brassard, P. 2011, ApJ, 737, L27
Randall, S. K., Fontaine, G., Geier, S., Van Grootel, V., &Brassard, P. 2014, A&A, 563, A79
Reed, M., Armbrecht, E., Telting, J., et al. 2018, MNRAS, 474, 5186
Reed, M. D., Kilkenny, D., O?Toole, S., et al. 2012, MNRAS, 421, 181
Reed, M. D., Telting, J. H., Ketzer, L., et al. 2019, MNRAS, 483, 2282
Reed, M. D., Yeager, M., Vos, J., et al. 2020, MNRAS, 492, 5202