ANALYSIS OF THE SOUTHERN PRE-CONTACT W UMA BINARY ZZ ERIDANI: A 34 YEAR PERIOD STUDY YIELDS A POSSIBLE LOW-MASS COMPANION

ABSTRACT Complete Bessel BVRI light curves of ZZ Eridani [2MASS J04130109-1044545, HV 6280, NSVS 14888164 (2000) = 04h13m1 s10, δ(2000) = −10°44′54 ″5 (ICRS), V = 13.9-14.4-15.0] are observed and analyzed. The system is a southern pre-contact W UMa binary. Its light curve has the appearance of an Algol (EA) light curve, however, it is made up of dwarf solar-type components with a period of only 0.4521 days. Our 34 year period study yields a sinusoidal fit or an increasing quadratic fit. The sinusoid may indicate that a third body is orbiting the close binary. The lower-limit mass of the third body is near that of the brown dwarf limit (0.095 M ). Also included is an improved ephemeris, a mass ratio search, and a simultaneous BVRI Wilson-Devinney solution.