New observations, photometric study and preliminary elements of the W UMa system DF CVn

Abstract

Abstract. CCD (V) light curve of the EW-type eclipsing variable DF CVn was obtained during seven nights in April-May, 2004. With our data we were able to determine 4 new times of minimum light. The light curve appears to exhibit a typical O'Connell effect, with Maximum I brighter than Maximum II by 0.013 mag. in V. Two Wilson-Devinney (WD) code working sessions, using the V light curve, were done with and without spots. The analysis of the results shows that the best fit was obtained with the spotted solution and indicates contact geometry. The photometric mass ratio of the system is found to be q = 0.347 and its inclination i = 72• , the primary minimum shows a transit. The star may be classified as an A-type W UMa system. Assuming a reasonable value for the mass of the primary component an estimate of the absolute elements of DF CVn has been made, with the assumption that the primary has a mass corresponding to its spectral type according to Straizys and Kuriliene (1981).