Determination of parameters of W UMa system. V. V757 Cen, ER Cep, AH Cnc

From photoelectric and spectroscopic data available in the literature, we bave determined the elements of three. W Ursae Majoris systems, by means of the Roche-model-based method of Wilson and Devinney. According to our solutions, the three systems (V757 Cen, ER Cep, AH Cnc) are a11 of W-type, that is primary minima are caused by occultation of the smaller (and less massive) component