The first photometric analysis of the W-subtype contact binary UCAC4 436-062932 with O'Connell effect

TL;DR

This paper presents the first photometric analysis of the W-subtype contact binary UCAC4 436-062932, revealing its shallow contact nature and the presence of the O'Connell effect, which is likely explained by star spots.

Contribution

It provides the first detailed light curve analysis of UCAC4 436-062932, identifying its W-subtype shallow contact configuration and supporting the spot model for the O'Connell effect.

Findings

Mass ratio approximately 2.7

Contact degree of 20%

O'Connell effect likely caused by star spots

Abstract

Two sets of light curves in $V$ $R_c$ $I_c$ bands for a newly discovered binary system UCAC4 436-062932 are obtained and analyzed using the Wilson-Devinney (W-D) code. The two sets of light curves get almost consistent results. The determined mass ratio is about $q = 2.7$ and the less massive component is nearly $250K$ hotter than the more massive one. The solutions conclude that UCAC4 436-062932 is a W-subtype shallow contact (with a contact degree of $f = 20\,\%$) binary system. Since the O'Connell effect appears on one set of the light curves, theories proposed to explain the effect are discussed. We assume that spot model may be the more plausible one to the O'Connell effect appeared on the asymmetric light curves of the binary system UCAC4 436-062932. Therefore, we add a cool spot on the surface of the more massive star (component with lower effective temperature) and get a quite approving results for the light curve fitting. It will provide evidence to support the spot model in the explanatory mechanism of O'Connell effect.