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Measurements of Abundances and Ages of Old Disk Clusters

Published online by Cambridge University Press:  14 August 2015

Alan Hirshfeld ,
Robert D. McClure  and
Bruce A. Twarog
Alan Hirshfeld
Affiliation:
Yale University Observatory
Robert D. McClure
Affiliation:
Yale University Observatory
Bruce A. Twarog
Affiliation:
Yale University Observatory

Extract

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The old disk clusters represent a striking contrast to the globular clusters which will be discussed extensively at this meeting in that the disk clusters show few anomalies. This makes a discussion of their abundance measurements of particular interest at this meeting, and may shed some light on the cause of the peculiar behavior of the halo objects. It is also appropriate to discuss the ages of the clusters since the HR diagram is a major tool for obtaining the ages of stars. A complete sequence of stars of one age in a cluster can be fitted to the ZAMS of theoretical models, and accurate abundances averaged over numerous stars in the cluster can be estimated. We will discuss the ages and abundances of 11 disk clusters for which UBV and DDO photometry are available in the literature. This limits the sample to those for which good color-magnitude (C-M) diagrams exist. In addition we present the C-M diagrams of two clusters that we have studied and that are not yet published elsewhere. We will use these clusters to illustrate our procedures.

Type
Part IV: HR Diagrams, Clusters
Information
Symposium - International Astronomical Union , Volume 80: The HR Diagram , 1978 , pp. 163 - 166
Copyright
Copyright © Reidel 1978 

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