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A determination of the thick disk chemical abundance distribution: Implications for galaxy evolutionWe present a determination of the thick disk iron abundance distribution obtained from an in situ sample of F/G stars. These stars are faint, 15 less than or approximately = V less than or approximately = 18, selected on the basis of color, being a subset of the larger survey of Gilmore and Wyse designed to determine the properties of the stellar populations several kiloparsecs from the Sun. The fields studied in the present paper probe the iron abundance distribution of the stellar populations of the galaxy at 500-3000 pc above the plane, at the solar Galactocentric distance. The derived chemical abundance distributions are consistent with no metallicity gradients in the thick disk over this range of vertical distance, and with an iron abundance distribution for the thick disk that has a peak at -0.7 dex. The lack of a vertical gradient argues against slow, dissipational settling as a mechanism for the formation of the thick disk. The photometric and metallicity data support a turn-off of the thick disk that is comparable in age to the metal-rich globular clusters, or greater than or approximately = 12 Gyr, and are consistent with a spread to older ages.
Document ID
19950061814
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gilmore, Gerard
(Institute of Astronomy, Cambridge, England United Kingdom)
Wyse, Rosemary F. G.
(University of California, Berkeley, CA United States)
Jones, Bryn J.
(University of Wales Wales, United Kingdom)
Date Acquired
August 16, 2013
Publication Date
March 1, 1995
Publication Information
Publication: Astronomical Journal
Volume: 109
Issue: 3
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
95A93413
Funding Number(s)
CONTRACT_GRANT: NSF INT-91-3306
CONTRACT_GRANT: NSF AST-88-07799
CONTRACT_GRANT: NSF AST-90-16226
Distribution Limits
Public
Copyright
Other

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