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Title: THE MULTI-COLOR LIGHT CURVES OF THE W UMa TYPE CONTACT BINARY EP ANDROMEDAE

New multi-color CCD photometric light curves of the eclipsing binary EP And were obtained over six nights in 2006, 2011, and 2012. Using the Wilson-Devinney code, we computed the photometric elements of this system. It was discovered that EP And is a W-type W UMa contact binary system with a mass ratio of q = 2.685 and a degree of contact factor f = 24.9%, rather than an A-type system. Combining 28 newly determined times of minimum light derived from 1999 to 2012 with others collected from the literature, a long-term increase (dP/dt = +5.22 Multiplication-Sign 10{sup -8} days yr{sup -1}) with a sinusoidal variation (A = 0.0109 days; T = 40.89 yr) in the orbital period was found. The orbital period secular increases may be interpreted as conservative mass transfer from the less massive component to the more massive one, and cyclic variations of the orbital period may be caused by the light-travel time effect through the presence of a third body. The evolutionary status and the age of the system are also discussed.
Authors:
; ; ; ; ;  [1]
  1. Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming (China)
Publication Date:
OSTI Identifier:
22136522
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 146; Journal Issue: 4; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; CHARGE-COUPLED DEVICES; COLOR; DIAGRAMS; ECLIPSE; MASS TRANSFER; VISIBLE RADIATION