A Analysis of the Light and Radial Velocity Curves of do CAS

DO Cas is a short period (P=0.68day) eclipsing binary star and is classified as a near-contact binary by Shaw (1990). There is no published radial velocity curve for this short period binary after Mannino (1958). Hill (1991) suspected that Mannino's radial velocity curve had some serious mistake. So, we scanned the original plates used by Mannino with PDS and the spectra were employed to IRAF packages to estimate the radial velocities. The radial velocity curve and the BVR light curves made by us in 1998 were analyzed simultaneously with Wilson-Devinney code. We found that DO Cas is a contact or near-contact binary which the primary component fills its Roche lobe and we also estimated the absolute dimensions of each components of this system