A study of the EB-type eclipsing binary GR Tauri with mass transfer

¹ National Astronomical Observatories/Yunnan Observatory, Joint laboratory for optical astronomy, Chinese Academy of Sciences, Kunming, PR China e-mail: shenggu@public.km.yn.cn
² Ho Koon Nature Education cum Astronomical Centre, Sik Sik Yuen, Hong Kong, PR China
³ Hong Kong Astronomical Society, Hong Kong, PR China

Received: 21 December 2001
Accepted: 10 May 2004

Abstract

In this paper, new CCD BV light curves of the EB-type eclipsing binary GR Tau, which were obtained in 1999, are analyzed by means of the Wilson-Devinney program. The photometric solution of this system is obtained, and its absolute parameters are also derived. Our study has demonstrated that GR Tau is a near-contact binary system with an almost-contact semidetached configuration in which the primary fills its Roche lobe, and both components are main-sequence stars. The asymmetric shape of the light curves can be explained by a hot spot on the surface of the secondary, which is created by the mass transfer from the primary to the secondary. GR Tau belongs to the V1010 Oph subclass of near-contact binaries, and is a good example of a system in the broken-contact phase predicted by the TRO theory.