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The gap in the color-magnitude diagram of NGC 2420: A test of convective overshoot and cluster ageTheoretical isochrones have been constructed using the OPAL opacities specifically to study the color-magnitude diagram of the open star cluster NGC 2420. This cluster provides a rare test of core convection in intermediate-mass stars. At the same time, its age is of interest because of its low metallicity and relatively high Galactic latitude for an open cluster. The excellent color-magnitude diagram constructed by Anthony-Twarog et al. (1990) allows a detailed fit of the isochrones to the photometric data. We discuss the importance of convective overshoot at the convective core edge in determining the morphology of the gap located near the main-sequence turnoff. We find that given the assumptions made in the models, a modest amount of overshoot (0.23 H(sub p)) is required for the best fit. Good agreement is achieved with all features of the turnoff gap for a cluster age of 2.4 +/- 0.2 Gyr. We note that a photometrically complete luminosity function near the main-sequence turnoff and subgiant branch would also provide an important test of the overshoot models.
Document ID
19950038771
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Demarque, Pierre
(Yale Univ. New Haven, CT, United States)
Sarajedini, Ata
(Yale Univ. New Haven, CT, United States)
Guo, X.-J.
(Yale Univ. New Haven, CT, United States)
Date Acquired
August 16, 2013
Publication Date
May 1, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 426
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A70370
Funding Number(s)
CONTRACT_GRANT: NAGW-2351
CONTRACT_GRANT: NAG5-1486
CONTRACT_GRANT: NAGW-2469
Distribution Limits
Public
Copyright
Other

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