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On the origin of metal homogeneities in globular clustersVarious transport processes which may have affected the chemical homogeneity in protocluster clouds are examined. It is shown that the characteristic diffusion time scale associated with collisions between grains and gas atoms is considerably longer than that on which star formation is expected to occur. Collisions between large grains and gas atoms lead to mass segregation and metallicity gradients on a time scale comparable to the crossing time of the clusters in the Galaxy. One possible mechanism for inducing and maintaining chemical homogeneity is turbulent diffusion in the clouds. The mixing time scale required in this case is comparable to several internal dynamical time scales, longer than the evolutionary time scale of the most massive stars, and shorter than the Galactic orbital time scale of the clouds. Thus, metals in presently observed stars probably did not originate from upper main-sequence stars of a coeval generation.
Document ID
19900052182
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Murray, Stephen D.
(Lick Observatory Santa Cruz, CA, United States)
Lin, Douglas N. C.
(Lick Observatory Santa Cruz, CA, United States)
Date Acquired
August 14, 2013
Publication Date
July 1, 1990
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 357
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
90A39237
Funding Number(s)
CONTRACT_GRANT: NGT-50281
CONTRACT_GRANT: NSF AST-83-01229
Distribution Limits
Public
Copyright
Other

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