We report the discovery of three pulsating subdwarf B stars in binary systems observed with the Kepler space telescope during Campaign 5 of K2. EPIC 211696659 (SDSS J083603.98+155216.4) is a g-mode pulsator with a white dwarf companion and a binary period of 3.16 d. EPICs 211823779 (SDSS J082003.35+173914.2) and 211938328 (LB 378) are both p-mode pulsators with main-sequence F companions. The orbit of EPIC 211938328 is long (635 ± 146 d) while we cannot constrain that of EPIC 211823779. The p modes are near the Nyquist frequency and so we investigate ways to discriminate super- from sub-Nyquist frequencies. We search for rotationally induced frequency multiplets and all three stars appear to be slow rotators with EPIC 211696659 subsynchronous to its orbit.
Physics, Astronomy, and Materials Science
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
stars oscillations, stars subdwarfs
Reed, Michael D., E. L. Armbrecht, John H. Telting, Andrzej S. Baran, R. H. Østensen, Pere Blay, Andreas Kvammen et al. "K2 Campaign 5 observations of pulsating subdwarf B stars: binaries and super-Nyquist frequencies." Monthly Notices of the Royal Astronomical Society 474, no. 4 (2018): 5186-5198.
Monthly Notices of the Royal Astronomical Society