Assessment of Stellar Stratification in Three Young Star Clusters in the Large Magellanic Cloud

TL;DR

This study investigates stellar stratification in three young Large Magellanic Cloud clusters using a new effective radius method, revealing varying degrees of stratification and proposing a quantitative parameter for comparison.

Contribution

Introduces a novel effective radius method to assess stellar stratification and develops a scheme for its quantitative comparison in young star clusters.

Findings

NGC 1983 is partially segregated for faint stars

NGC 2002 shows strong stratification for all stars

NGC 2010 exhibits no stratification

Abstract

(abridged) We present a comprehensive study of stellar stratification in young star clusters in the Large Magellanic Cloud (LMC). We apply our recently developed effective radius method for the assessment of stellar stratification on imaging data obtained with the Advanced Camera for Surveys of three young LMC clusters to characterize the phenomenon and develop a comparative scheme for its assessment in such clusters. The clusters of our sample, NGC 1983, NGC 2002 and NGC 2010, are selected on the basis of their youthfulness, and their variety in appearance, structure, stellar content, and surrounding stellar ambient. Our photometry is complete for magnitudes down to m_814 ~ 23 mag, allowing the calculation of the structural parameters of the clusters, the estimation of their ages and the determination of their stellar content. Our study shows that each cluster in our sample demonstrates stellar stratification in a quite different manner and at different degree from the others. Specifically, NGC 1983 shows to be partially segregated only for the faintest stars of the cluster, NGC 2002 shows evidence of strong stellar stratification for both bright and faint stars, and NGC 2010 is found not to be segregated. For the parametrization of the phenomenon of stellar stratification and its quantitative comparison among these clusters, we propose the slope derived from the change in the effective radius over the corresponding magnitude range as indicative parameter of the degree of stratification in the clusters. A positive value of this slope indicates mass segregation in the cluster, while a negative or zero value signifies the lack of the phenomenon.