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Title: Photometric analysis of the overcontact binary CW Cas

New CCD photometric observations of overcontact binary CW Cas were carried out in 2004 and 2011. In particular, the light curve obtained in 2004 shows a remarkable O'Connell effect. Compared with light curves in different observing seasons, variations were found. These variations can be explained by dark spot activities on the surface of at least one component. Using the Wilson-Devinney code with a spot model, we find that the photometric solutions confirm CW Cas is a shallow W-subtype overcontact binary with a spotted massive component. Our new determined times of minimum light together with the others published in the literature were analyzed to find a change of orbital period. From the O – C curves, the period of the system shows a cyclic period change (P {sub 3} = 69.9 yr, A {sub 3} = 0.03196 days) superposed on the linear increase. The cyclic variation, if explained as the light-travel time effect, reveals the presence of a tertiary companion.
Authors:
; ; ; ;  [1]
  1. National Astronomical Observatories/Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming (China)
Publication Date:
OSTI Identifier:
22342222
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 5; 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; COMPARATIVE EVALUATIONS; ECLIPSE; MATHEMATICAL SOLUTIONS; STARS; SURFACES; VARIATIONS; VISIBLE RADIATION