Photometric investigation of the contact binary GU Orionis with high metallicity

Abstract

Abstract GU Ori was observed with the 1 m telescope at Yunnan Observatories in 2005. To determine its physical properties, the Wilson–Devinney program was used. The results reveal that GU Ori is a W-subtype shallow contact binary with a more massive but cooler second star. The masses of its two component stars are estimated to be M1 = 0.45 M⊙, M2 = 1.05 M⊙. The O’Connell effect was reported to be negative on the light curves observed in 2005. However, it changed to a positive one on the light curves observed from 2011 to 2012. The mean surface temperatures of star 2 (T2) determined by the two sets of light curves were different, which may result from stellar activity. The O − C diagram shows that the period of GU Ori is decreasing at a rate of dP/dt = −6.24 × 10−8d yr−1, which may be caused by mass transfer from star 2 to star 1 with a rate of ${dM_{2}}/{dt}= - 2.98\times {10^{-8}}\, M_{\odot }$ yr−1. GU Ori is a contact binary with quite high metallicity.