NY Vir Eclipse timing observations: Two planet solution

Abstract

We report 18 new primary minima timing observations of the short-period eclipsing binary system NY Virginis. We combined these minima with previously published primary minima to update circumbinary exoplanet models in this system based on O-C timing variations. We performed a non-linear least-squares minimization search using a quadratic ephemeris and either one or two exoplanets. The only model with an acceptable fit includes a period derivative $\dot{P}=2.83\times 10^{-12}$ and two planets in eccentric orbits $e=0.15,0.15$ with minimum masses 2.7 and 5.5 Jovian masses. Analysis of the orbit stability shows that this solution is stable for at least $10^8$ yr, but a small increase in eccentricity ($e\ge 0.20$) for either planet renders the orbits unstable in less than $10^6$ years. A number of model parameters are significantly degenerate, so additional observations are required to determine planetary parameters with high statistical confidence.