http://arxiv.org/abs/1510.05465
We report the discovery of four short-period eclipsing systems in the Kepler light curves, consisting of an A-star primary and a low-mass white-dwarf (WD) secondary (dA+WD) – KIC 4169521, KOI-3818, KIC 2851474 and KIC 9285587. The systems show BEaming, Ellipsoidal and Reflection (BEER) phase modulations together with primary and secondary eclipses. These add to the 6 Kepler, and 18 WASP, previously known short-period eclipsing dA+WD binaries. The light curves together with follow-up spectroscopic observations allow us to derive the masses, radii and effective temperatures of the two components of the four systems. The orbital periods, of 1.17-3.82 d, and WD masses, of 0.19-0.22 Msun, are similar to those of the previously known systems. The WD radii of KOI-3818, KIC 2851474, and KIC 9285587 are 0.026, 0.035 and 0.026 Rsun, respectively, the smallest WD radii derived so far for short-period eclipsing dA+WD binaries. These three binaries extend the previously known population to older systems with cooler and smaller WD secondaries. KOI-3818 displays evidence for a fast-rotating primary and a minute but significant eccentricity of ~0.0015. These features are probably the outcome of the mass-transfer process.
S. Faigler, I. Kull, T. Mazeh, et. al.
Tue, 20 Oct 15
50/92
Comments: 28 pages, 7 figures and 4 tables. Revised submission to The Astrophysical Journal in response to a referee report
You must be logged in to post a comment.