BL Eridani: An unstable W Ursae Majoris system with spotted components

Abstract

New complete BV light curves of BL Eri are presented. Light-curve variability and asymmetry are seen in both B and V bands, and the observed times of light minimum indicate period changes. The light curves have been analyzed by using the light-curve-synthesis method. Our photometric solution reveals that BL Eri is a contact binary with a common convective envelope. An examination of the available photometric and spectroscopic data indicates that the light-curve variability may be due to changes of the component radii and the light-curve asymmetry may be consistent with starspot activity on one or both components.