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High-resolution CCD spectra of stars in globular clusters. III - M4, M13, and M22Spectra of 0.3 and 0.6 A resolution of stars in M4, M13 and M22 to derive abundances of various atomic species and the CN molecule. For M13, the usual Fe/H ratio and a surprisingly high aluminum abundance is found. The CN lines indicate a larger column density in the oxygen-rich star III-63 than in the oxygen-poor star II-67 by a factor of 10. It appears that II-67 is deficient in C, N, and O by about a factor 3 relative to iron for all three elements. For M4, Fe/H = -1.2 using solar f values derived via the Bell et al. (1976) model. This Fe abundance lies between earlier echelle values and photometric values. For two stars, CN data are obtained that can be understood if there was a slight excess of C/Fe and N/Fe prior to CN cycling and mixing. For M22, a large difference in CN is found between stars III-3 and IV-102. The origin of the CNO elements is discussed in terms of mass loss from an early generation of red giants and possibly Wolf-Rayet stars.
Document ID
19870053189
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wallerstein, George
(Washington Univ. Seattle, WA, United States)
Leep, E. Myckky
(Washington, University Seattle, United States)
Oke, J. B.
(Palomar Observatory Pasadena, CA, United States)
Date Acquired
August 13, 2013
Publication Date
May 1, 1987
Publication Information
Publication: Astronomical Journal
Volume: 93
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
87A40463
Funding Number(s)
CONTRACT_GRANT: NSF AST-84-15353
CONTRACT_GRANT: NGL-05-002-134
Distribution Limits
Public
Copyright
Other

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