PHOTOMETRIC AND SPECTROSCOPIC OBSERVATIONS OF THE 53 PERSEI-TYPE STARS - ZETA-CASSIOPEIAE

We present the results of photometric and spectroscopic observations o f the star zeta Cas. The luminosity fluctuations are inside 0.004 magn itude in the u, v and b Stromgren's filters. For a given night the rad ial velocity measurements vary inside 1 kms-1. We suppose that the obs erved night to night radial velocity variations are due to a close bin arity. The orbital period could be 11.53 days with a 2K amplitude equa l 3.6 kms-1. The full width at half maximum (FWHM) measurements of the 4552 angstrom SiIII line are variable from night to night inside 0.08 angstrom. After detrending for this variation, a peak appears in the power spectrum at 0.27 day with a half amplitude of 0.01 angstrom poss ibly due to a non radial g mode. We do not detect the 0.9 d. period de termined by Smith (1980). So the only short time variable parameter is the shape of the line profile. This is the main characteristic of a 5 3 Per type star.