Chromospheric activity and unique solution of SZ Psc

Abstract

We have confirmed that the Mg ii h and k emission lines of SZ Psc are mainly enhanced by the K subgiant component of the system, using the radial velocities reduced from the emission lines. The intensity variation of the emission line is correlated with the orbital phase of SZ Psc. The shape of light curves of SZ Psc were changing every season. The three representative light curves of three different epochs, 1978, 1979 and 1981, were selected to find a unique solution of SZ Psc which can explain the variation of light curves. The binary parameters, including inclination, mass ratio, temperatures and potentials of both components for the three epochs coincide, although the shapes of light curves for three epochs are different from each other. Changing only spot parameters, the model light curves fit to the observed light curves for three epochs. This means that the variation of spot location and size is the main reason for changing the shape of light curves.