First Photometric Analysis of the Solar-Type Binary, V428 (NSV 395), in the field of NGC 188

摘要

V428 (or NSV 395) is a faint 15th magnitude binary observed in a study of the open cluster NGC188. However, its distance from the core of the cluster might exclude its membership. Its light curve was classified as a short period EB type eclipsing binary with a period of 0.3079 d and an amplitude of -0.7 magnitude in all curves. The difference in component temperatures is some ΔT = 180 K and its fill-out is a hefty 35%. A brief, 2.5 year period study yields, as expected, a constant period, which is 0.3076789 d. More monitoring is needed to determine its true orbital evolution. The inclination, 80° is not quite enough to produce total eclipses, so a q-search was performed using the September 17, 2004 version of the Wilson-Devinney program. Our lowest residual solution gives a q = 0.4. A cool spot was modeled on the primary component to take care of the light curve asymmetries. V428 is a K-type W UMa contact binary.