CCD Photometric Investigation of A W UMa-Type Binary GSC 0763-0572

Abstract

A photometric solution of an A-type W UMa binary, GSC 0763-0572 is examined with a revised orbital period. The overcontact degree is found to be $f$ = 40.66%, with a low mass ratio of $q$ = 0.2554. The result demonstrates an unambiguous increase in the orbital period with a relative period change of $\Delta P\slash P = +5.69\times10^{-7} $d yr$^{-1}$. This indicates that GSC 0763-0572 is undergoing a process of mass transfer from the secondary component to the primary one with a rate of relative mass change of $\Delta$$m_1$$\slash$$m$ $=+5.18\times10^{-8}$ yr$^{-1}$, for a conservative model of mass transfer. We find that GSC 0763-0572 might transform into a rapidly rotating star, if total spin angular momentum increases until it is greater than one-third of the orbital angular momentum, without breaking the contact configuration.