How fast is mass-segregation happening in hierarchical formed embedded star clusters?

TL;DR

This study uses N-body simulations to analyze how quickly mass segregation occurs in young embedded star clusters with various initial conditions, finding that clusters tend to rapidly become mass segregated and spherical regardless of their initial state.

Contribution

It demonstrates that mass segregation in embedded star clusters happens quickly and is largely independent of initial conditions, providing insights into cluster evolution.

Findings

Clusters rapidly become mass segregated and spherical.

Initial conditions influence the speed of segregation.

Mass segregation is almost inevitable once clusters appear spherical.

Abstract

We investigate the evolution of mass segregation in initially sub-structured young embedded star clusters with two different background potentials mimicking the gas. Our clusters are initially in virial or sub-virial global states and have different initial distributions for the most massive stars: randomly placed, initially mass segregated or even inverse segregation. By means of N-body simulation we follow their evolution for 5 Myr. We measure the mass segregation using the minimum spanning tree method Lambda_MSR and an equivalent restricted method. Despite this variety of different initial conditions, we find that our stellar distributions almost always settle very fast into a mass segregated and more spherical configuration, suggesting that once we see a spherical or nearly spherical embedded star cluster, we can be sure it is mass segregated no matter what the real initial conditions were. We, furthermore, report under which circumstances this process can be more rapid or delayed, respectively.