An analysis of the light curves of short-period RS Canum Venaticorum stars - Starspots and fundamental properties

Abstract

An analysis is performed of selected light curves for the short-period RS CVn group: UV Psc, XY UMa, RT And, SV Cam, BH Vir, ER Vul, WY Cnc, and Cg Cyg. The photometric fitting parameters are optimized for the 'distorted' light curves in order to derive the maculation wave for each system. A dark circular spot model is fitted to the maculation wave to infer the longitudes and sizes of one or two spot groups presumed to account for these effects. Using these spot properties, the original light curves are cleaned of their distortion waves and new, optimal solutions are found, which give the adopted geometrical, orbital, and physical parameters for the stars of these systems, which fall on the lower end of the main sequence. It is concluded that the secondary stars in these systems are all main sequence rather than subgiants typical for RS CVn binaries.