On the Possibility to Estimate the Orbital Eccentricity of a Binary System with an Exoplanet from a Transit Light Curve

Abstract We study the possibility of determining an orbital eccentricity of a binary star system with an exoplanet from both simulated and observed transit light curves. It has been shown that an exact value of the eccentricity can be contained from transit light curves, if the longitude of periastron is known. If the information about the longitude of periastron is not available, the analysis of the transit light curve makes it possible to impose limits on values of the orbital eccentricity. We study the influence of the uncertainty in the orbital eccentricity on the accuracy of determining the other parameters of the system (the radii of the star and the planet, the orbital inclination, and the limb darkening coefficient).