Dynamical Evolution of Multiple-Population Globular Clusters

TL;DR

This study uses Monte Carlo simulations to investigate the dynamical evolution of multiple stellar populations in globular clusters, focusing on their spatial mixing, star escape, and velocity anisotropy over time.

Contribution

It provides new insights into how initial conditions affect the long-term dynamical behavior and spatial distribution of multiple populations in globular clusters.

Findings

Fraction of 2G stars evolves with dynamical processes.

Spatial mixing of 1G and 2G stars occurs over time.

Velocity anisotropy varies with cluster evolution stage.

Abstract

We have carried out a set of Monte Carlo simulations to study a number of fundamental aspects of the dynamical evolution of multiple stellar populations in globular clusters with different initial masses, fractions of second generation (2G) stars, and structural properties. Our simulations explore and elucidate: 1) the role of early and long-term dynamical processes and stellar escape in the evolution of the fraction of 2G stars and the link between the evolution of the fraction of 2G stars and various dynamical parameters; 2) the link between the fraction of 2G stars inside the cluster and in the population of escaping stars during a cluster's dynamical evolution; 3) the dynamics of the spatial mixing of the first-generation (1G) and 2G stars and the details of the structural properties of the two populations as they evolve toward mixing; 4) the implications of the initial differences between the spatial distribution of 1G and 2G stars for the evolution of the anisotropy in the velocity distribution and the expected radial profile of the 1G and 2G anisotropy for clusters at different stages of their dynamical history; 5) the variation of the degree of energy equipartition of the 1G and the 2G populations as a function of the distance from the cluster's centre and the cluster's evolutionary phase.