A Photometric Study of the Near-Contact Binary WY Tauri

Abstract

Abstract CCD photometric observations for the eclipsing binary WY Tauri are firstly presented. Three new minimum timings in 2006 and 2008 have been determined. Using Wilson–Devinney binary code, the photometric solution was simultaneously deduced from $VR$ light curves. Photometric results indicate that WY Tau is a semi-detached binary, whose secondary component fills its Roche lobe. The mass ratio and orbital inclination are $q$$=$ 0.508($\pm$0.006) and $i$$=$ 78${\rlap{\hskip.75pt{^\circ}}\hskip.75pt.\hskip1pt}$0($\pm$0${\rlap{\hskip.75pt{^\circ}}\hskip.75pt.\hskip1pt}$05), respectively. The filling factor of the primary component is 84.9%, indicating that this star is a near-contact binary. Based on all available eclipse timings since 1930, it is found that the ($O-C$) curve may be described by either a long-term period increase or a cyclic variation. The continuous period increase at a rate of $dP/dt$$=$$+$4.65 $\times$ 10$^{-8} $d yr$^{-1}$ may be attributed to mass transferring from the secondary to the primary, identified by the semidetached configuration. With mass transferring, WY Tau may evolve into a contact binary.