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

TL;DR

This paper presents the first photometric analysis of the totally eclipsing contact binary V811 Cep, revealing its contact nature, mass ratio, and period decrease, with implications for mass transfer dynamics.

Contribution

It provides the first complete light curves and detailed analysis of V811 Cep, including its contact degree, subtype, and period variation, using Wilson-Devinney modeling.

Findings

V811 Cep is a median-contact W-subtype binary with 33.9% contact degree.

The binary exhibits a total eclipse with an inclination of 88.3°.

The orbital period is decreasing, indicating mass transfer from the more massive to less massive component.

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 Wilson-Devinney (W-D) program, and the results show that V811 Cep is a median-contact binary ($f=33.9(\pm4.9)\%$) 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 $i=88.3^{\circ}$, 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 $\dot{P}=-3.90(\pm0.06)\times 10^{-7}d \cdot yr^{-1}$, which indicates that the mass transfer occurs from the more massive component to the less massive one.