A photometric survey of the eclipsing RS CVn-type system RZ Eridani : starspot variability, circumstellar matter, tidal evolution.

Abstract

Results are presented of monitoring of the RS CVn-type eclipsing binary RZ Eridani, observed in the seven colors of the Geneva photometric system between November 1977 and April 1989. It is shown that the primary is an A8-F0IV star, which was stable during the 12 years of the survey. The secondary component, a G8-K0IV-III star, exhibits three kinds of stellar variability: a starspot effect with a period of about 35 d (stellar rotation), varying from year to year; a reflection effect of the light from the primary component, with a period equal to the orbital one (the orbital period); and a long-term variability, tentatively attributed to be due to a stellar activity cycle.