BL Eri: A Contact Binary System (Abstract)

Volume 37 number 2 (2009)

Lee Snyder

Abstract

(Abstract only) BL Eri is a W-type W UMa system with a mass ratio of 0.546 and a contact parameter f = 0.2 for the primary star, indicating over-contact, and f = –0.0008 for the secondary, indicating near-contact. The system stars have low surface temperature and a short period of 0.42 day. New CCD photometric light curves in V and R bands and computed parameters solutions using a light curve synthesis program are presented. Prior visual, photographic, and photoelectric observations from February 1978 through October 2004 are analyzed along with this paper data obtained in October 2008. O–C data have been analyzed using a linear ephemeris but were better described by a quadratic ephemeris. The first time radial velocity curves of BL Eri were obtained in 1988 and used to compute the mass ratio of the system along with prior observational data used to compute the physical quantities of the system. The spectral type, orbital period, and angular momentum changes are discussed.