The gap in the color-magnitude diagram of NGC 2420: A test of convective overshoot and cluster age

Abstract

view Abstract Citations (62) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Gap in the Color-Magnitude Diagram of NGC 2420: A Test of Convective Overshoot and Cluster Age Demarque, Pierre ; Sarajedini, Ata ; Guo, X. -J. Abstract Theoretical 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 Hp) 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. Publication: The Astrophysical Journal Pub Date: May 1994 DOI: 10.1086/174052 Bibcode: 1994ApJ...426..165D Keywords: Color-Magnitude Diagram; Galactic Evolution; Opacity; Open Clusters; Stellar Convection; Stellar Evolution; Stellar Interiors; Stellar Models; Astronomical Photometry; Curve Fitting; Metallicity; Astrophysics full text sources ADS | data products SIMBAD (1)