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

Abstract

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 newmid-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 a_c sin i_c ~1.9AU and a_d sin i_d ~ 2.9AU. The masses of the external bodies would be Mc ~2.9M_Jupiter and Md ~8.1M_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.