TWO POSSIBLE CIRCUMBINARY PLANETS IN THE ECLIPSING POST-COMMON ENVELOPE SYSTEM NSVS 14256825*

摘要

We present an analysis of eclipse timings of the post-common envelope binary NSVS?14256825, which is composed of an sdOB star and a dM star in a close orbit (P orb = 0.110374 days). High-speed photometry of this system was performed between 2010 July and 2012 August. Ten new mid-eclipse times were analyzed together with all available eclipse times in the literature. We revisited the (O – C) diagram using a linear ephemeris and verified a clear orbital period variation. On the assumption that these orbital period variations are caused by light travel time effects, the (O – C) diagram can be explained by the presence of two circumbinary bodies, even though this explanation requires a longer baseline of observations to be fully tested. The orbital periods of the best solution would be Pc ~ 3.5 years and Pd ~ 6.9 years. The corresponding projected semi-major axes would be ac sin ic ~ 1.9 AU and ad sin id ~ 2.9 AU. The masses of the external bodies would be Mc ~ 2.9 M Jupiter and Md ~ 8.1 M Jupiter, if we assume their orbits are coplanar with the close binary. Therefore NSVS?14256825 might be composed of a close binary with two circumbinary planets, though the orbital period variations is still open to other interpretations.