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IUE spectrophotometry of the DA4 primary in the short-period white dwarf-red dwarf spectroscopic binary Case 1Low-resolution ultraviolet International Ultraviolet Explorer spectra of the DA white dwarf Case 1 are presented. The spectra show the presence of the 1400 A feature, already discovered in several other DA stars, and of a shallower trough in the 1550-1700 A range. A model atmosphere analysis of the ultraviolet energy distribution of the Ly-alpha red wing yields T(e) = 13,000 + or - 500 K. Possible interpretations of the 1400 A feature are reviewed. Case 1 is the coolest white dwarf found in a short-period, detached white dwarf-red dwarf binary, and its cooling time is consistent with estimates of the efficiency of angular momentum removal mechanisms in the phases subsequent to common envelope binary evolution.
Document ID
19840050797
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sion, E. M.
(Villanova Univ. PA, United States)
Guinan, E. F.
(Villanova University Villanova, PA, United States)
Wesemael, F.
(Observatoire du Mont Megantic, Quebec; Montreal, Universite Montreal, Canada)
Date Acquired
August 12, 2013
Publication Date
April 15, 1984
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 279
ISSN: 0004-637X
Subject Category
Astrophysics
Funding Number(s)
CONTRACT_GRANT: NSG-5375
Distribution Limits
Public
Copyright
Other
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