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Ultraviolet colors of W Ursae Majoris - Gravity darkening, temperature differences, and the cause of W-type light curvesThe paper presents photometry of the prototype W UMa binary system in three ultraviolet bands with the ANS satellite. It was found that W UMa has low-gravity darkening beta of 0.03; that temperature differences between the components not established by gravity darkening are insignificant; and that the bolometric albedo is not very large. It was also found that W UMa is limb-darkened in the ultraviolet region, and that the inner hemisphere of the less massive component is hotter than that predicted by gravity darkening and the reflection effect. It was concluded that about 20% of the surface area of the component responsible for large gravity darkening is covered by dark spots distributed uniformly in the longitudinal direction. An observational value of the convective darkening exponent of 0.054 plus or minus 0.02 is proposed.
Document ID
19800068199
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Eaton, J. A.
(Polska Akademia Nauk Centrum Astronomiczne, Warsaw, Poland)
Wu, C.-C.
(Computer Sciences Corp. Silver Spring, Md., United States)
Rucinski, S. M.
(Observatorium Astronomiczne Warsaw, Poland)
Date Acquired
August 10, 2013
Publication Date
August 1, 1980
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
80A52369
Funding Number(s)
CONTRACT_GRANT: NSF INT-76-80588
CONTRACT_GRANT: NASW-3254
Distribution Limits
Public
Copyright
Other

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