Photometric study of AH Cancri, a WUMa-type system in M67

We present time-series CCD photometry of AH Cnc, a W UMa-type binary system in the old open cluster M67. Over 3500 measurements in two filters were recorded on 15 nights from 2001 to 2004. From the data, 17 new times of minima for the eclipsing binary were obtained, from which a new ephemeris was derived. The orbital period of the system is refined as 0.36045754 days. A photometric analysis for the obtained light curves is performed based on the Wilson-Devinney code. The photometric solutions reveal a totally eclipsing contact configuration for AH Cnc. The photometric mass ratio is determined to be 0.149 +/- 0.002. The masses and radii of the components are estimated as 1.21 +/- 0.08 M-circle dot and 1.36 +/- 0.03 R-circle dot for the primary and 0.18 +/- 0.02 M-circle dot and 0.62 +/- 0.02 R-circle dot for the secondary, respectively. The evolutionary status of the contact system is briefly discussed.