Journal Article

First <i>Kepler</i> results on compact pulsators – II. KIC 010139564, a new pulsating subdwarf B (V361 Hya) star with an additional low-frequency mode

S. D. Kawaler, M. D. Reed, A. C. Quint, R. H. Østensen, R. Silvotti, A. S. Baran, S. Charpinet, S. Bloemen, D. W. Kurtz, J. Telting, G. Handler, H. Kjeldsen, J. Christensen-Dalsgaard, W. J. Borucki and D. G. Koch

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 409, issue 4, pages 1487-1495
Published in print December 2010 | ISSN: 0035-8711
Published online December 2010 | e-ISSN: 1365-2966 | DOI: https://dx.doi.org/10.1111/j.1365-2966.2010.17528.x
First Kepler results on compact pulsators – II. KIC 010139564, a new pulsating subdwarf B (V361 Hya) star with an additional low-frequency mode

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We present the discovery of non-radial pulsations in a hot subdwarf B star based on 30.5 d of nearly continuous time series photometry using the Kepler spacecraft. KIC 010139564 is found to be a short-period pulsator of the V361 Hya (EC 14026) class with more than 10 independent pulsation modes whose periods range from 130 to 190 s. It also shows one periodicity at a period of 3165 s. If this periodicity is a high-order g-mode, then this star may be the hottest member of the hybrid DW Lyn stars. In addition to the resolved pulsation frequencies, additional periodic variations in the light curve suggest that a significant number of additional pulsation frequencies may be present. The long duration of the run, the extremely high duty cycle and the well-behaved noise properties allow us to explore the stability of the periodic variations, and to place strong constraints on how many of them are independent stellar oscillation modes. We find that most of the identified periodicities are indeed stable in phase and amplitude, suggesting a rotation period of 2–3 weeks for this star, but further observations are needed to confirm this suspicion.

Keywords: stars: oscillations; subdwarfs; stars: variables: general

Journal Article.  6158 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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