Young Clusters in the Magellanic Clouds. II.

Abstract

We present the results of a quantitative study of the degree of extension to the boundary of the classical convective core within intermediate-mass stars. The basis of our empirical study is the stellar population of four young populous clusters in the Magellanic Clouds that has recently been detailed by Keller, Bessell, & Da Costa. The sample affords a meaningful comparison with theoretical scenarios with varying degrees of convective core overshoot and binary star fraction. Two critical properties of the population, the main-sequence luminosity function and the number of evolved stars, form the basis of our comparison between the observed data set and that simulated from the stellar evolutionary models. On the basis of this comparison we conclude that the case of no convective core overshoot is excluded at a 2 σ level. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.