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The FK Comae candidate UX LibraeNew optical spectroscopic and photometric data are presented for the active chromosphere FK Com candidate UZ Lib. The star is shown to have an extremely large photometric amplitude in V of 0.35 mag, and its rotation period is established as 4.75 + or - 0.01 days. The optical spectrum is that of an early K giant, broadened by a rotation velocity of approximately 65 km/s. H-alpha is visible as a very broad emission feature, with a profile resembling that seen in FK Com. The emission intensity and profile are variable over the rotation period, with the strongest emission present at photometric minimum, in accord with dark starspot models. The photospheric absorption line profiles show variable asymmetries and distortions which are interpreted as due to the effects of the dark starspot rotating across the line of sight. New radial velocity measures are combined with published data to demonstrate the UZ Lib is a member of a binary system in synchronous rotation with a secondary of mass approximately 0.5 solar masses. This information is considered in light of the conflicting models for the origin of the optical and spectral variability of the FK Com stars, as well as their uncertain evolutionary status.
Document ID
19850031695
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Bopp, B. W.
(Ritter Observatory; Toledo, University Toledo, OH; Kitt Peak National Observatory, Tucson, AZ, United States)
Goodrich, B. D.
(Ritter Observatory Toledo, OH, United States)
Africano, J. L.
(Kitt Peak National Observatory Tucson, AZ, United States)
Noah, P. V.
(Ritter Observatory Toledo, OH, United States)
Meredith, R. J.
(Ritter Observatory; Toledo, University Toledo, OH, United States)
Palmer, L. H.
(Simon Frazer University Burnaby, British Columbia, Canada)
Quigley, R. J.
(Western Washington University Bellingham, WA, United States)
Date Acquired
August 12, 2013
Publication Date
October 1, 1984
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 285
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
85A13846
Funding Number(s)
CONTRACT_GRANT: NAGW-229
CONTRACT_GRANT: NSF AST-81-15098
Distribution Limits
Public
Copyright
Other

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