Spectroscopic and photometric analysis of three detached binary systems: AP And, VZ Cep and V881 Per

We present results from analysis of combined spectroscopic and photometric data for three eclipsing binary systems: AP And, VZ Cep and V881 Per. Based on new, multicolour photometric light curves and spectroscopically determined mass ratio values, we derived accurate physical parameters of the components. Two of the systems, namely VZ Cep and V881 Per, were found to be magnetically active. The variability of V881 Per was studied in several sets of data [Northern Sky Variability Survey (NSVS), Wide Angle Search for Planets (WASP) and newly derived] gathered at different epochs. We show that the huge differences in the shape of its light curve can be explained by just a single model differing only in number of spots and their location on the surface of the primary component.