Effects of stellar collisions on star cluster evolution and core collapse

TL;DR

This study uses Monte Carlo simulations to explore how stellar collisions influence the evolution and observable properties of dense star clusters, revealing that collisions can prevent core collapse depending on stellar lifetimes.

Contribution

It introduces a detailed analysis of collision effects on cluster evolution, considering the lifetimes of massive collision products, a novel aspect in the field.

Findings

Stellar collisions can alter core radii and radial distributions.

Collisions may prevent core collapse without binaries.

Observable properties depend on lifetimes of massive collision products.

Abstract

We systematically study the effects of collisions on the overall dynamical evolution of dense star clusters using Monte Carlo simulations over many relaxation times. We derive many observable properties of these clusters, including their core radii and the radial distribution of collision products. We also study different aspects of collisions in a cluster taking into account the shorter lifetimes of more massive stars, which has not been studied in detail before. Depending on the lifetimes of the significantly more massive collision products, observable properties of the cluster can be modified qualitatively; for example, even without binaries, core collapse can sometimes be avoided simply because of stellar collisions.