Photometric Study of W UMa type Eclipsing Binary GM Bootis

GM Boo is a short period (~0.36 days) contact binary system discovered for over 10 years. In this work, new multi-color photometric light curves from 2010 to 2015 and low-resolution spectra of GM Boo are obtained. We extracted 19 new eclipse timings of GM Boo from the light curves, deriving a long-term increasing rate of the orbital period dP/dt=1.06×10^-7d·yr^-1 combined with historical data. Photometric solution is derived with the Wilson-Devinney Code, which shows that GM Boo is a typical W-type contact binary with mass ratio of q~1.22 and contact degree of ~11%. Two cool spots are assumed in the model in order to fit the asymmetrical light curves, which indicate that GM Boo is an active system.s