The first photometric analysis of the totally eclipsing contact binary V811 Cep

Abstract The first photometric analysis of V811 Cep was carried out. The first complete light curves of V , R and I bands are given. The analysis was carried out by the Wilson-Devinney (W-D) program, and the results show that V811 Cep is a median-contact binary ( f = 33.9(±4.9)%) with a mass ratio of 0.285. It is a W-subtype contact binary, that is, the component with less mass is hotter than the component with more mass, and the light curves are asymmetric (O’Connell effect), which can be explained by the existence of a hot spot on the component with less mass. The orbital inclination is i = 88.3°, indicating that it is a totally eclipsing binary, so the parameters obtained are reliable. Through the O-C analyzing, it is found that the orbital period decreases at the rate of Ṗ = −3.90(±0.06) × 10 −7 d yr −1 , which indicates that the mass transfer occurs from the more massive component to the less massive one.