2012A&A...543A.138B

We report new mid-eclipse times of the short-period sdB/dM binary HW Virginis, which differ substantially from the times predicted by a previous model. The proposed orbits of the two planets in that model are found to be unstable. We present a new secularly stable solution, which involves two companions orbiting HW Vir with periods of 12.7yr and 55±15yr. For orbits coplanar with the binary, the inner companion is a giant planet with mass M₃sini₃≃14M_Jup and the outer one a brown dwarf or low-mass star with a mass of M₄sini₄= 30-120M_Jup. Using the mercury6 code, we find that such a system would be stable over more than 10⁷yr, in spite of the sizeable interaction. Our model fits the observed eclipse-time variations by the light-travel time effect alone, without invoking any additional process, and provides support for the planetary hypothesis of the eclipse-time variations in close binaries. The signature of non-Keplerian orbits may be visible in the data.