An Updated Model for Circumbinary Planets Orbiting the sdB Binary NY Virginis

Abstract

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 nonlinear 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 and two planets in eccentric orbits e = 0.15, 0.15 with minimum masses of 2.7 and 5.5 Jovian masses. Analysis of the orbit stability shows that this solution is stable for at least 10 8 years, but a small increase in eccentricity ( e ≥ 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.