A Model for Contact Binary EP Andromedae

Abstract

AbstractThis paper presents the first comprehensive study of the EP And system, a contact binary. In this work the solution of the standard V light curve was obtained using the phoebe program (version 0.3c). Absolute parameters of the stellar components were then determined, enabling us to discuss the structure and evolutionary status of the close binary EP And. The times of minima data (‘O–C curve’) were analyzed. It was found that a third body with a period of 41.20 yr and mass 0.15 M⊙ is orbiting around the system. Also a modulating period of an 11.72-yr cycle along with a relative period increase of = 1.79 × 10−7 were obtained, which were attributed to the magnetic activity cycle and mass transfer with rate = 9.98 × 10−8 yr−1 between the components, respectively.