KW Persei - a near-contact system?

An analysis of UBV photoelectric photometry for the eclipsing binary KW Per based on new observational data is presented. The light changes are not on ly due to eclipses, but also to activity in the system. The U, B and V ligh t curves are analyzed by the Binary Maker 2.0 and Wilson-Devinney codes to derive the geometrical and physical parameters of the system. Since the O'C onnell effect is present on the light curves in the three colours, the unpe rturbed parts of the light curves are considered to represent the quiet sta ge of the system, in contrast to the active stage which is represented by t he perturbed parts of the light curves. The discussion about the evolutiona ry status of the system indicates that the secondary component of the binar y system is an evolved star and the primary is a MS star.