Investigating mass segregation process in globular clusters with Blue Straggler Stars: the impact of dark remnants

TL;DR

This study uses N-body simulations to examine how dark remnants like black holes influence the mass segregation of blue straggler stars in globular clusters, introducing a new parameter to track this process.

Contribution

The paper introduces a new parameter, $A^+$, to measure BSS segregation and demonstrates its potential as an indicator of cluster core collapse timing.

Findings

Black holes delay mass segregation of BSSs.

The $A^+$ parameter correlates with cluster evolution stages.

Dark remnants significantly impact cluster dynamical processes.

Abstract

We present the results of a set of N-body simulations aimed at exploring how the process of mass segregation (as traced by the spatial distribution of blue straggler stars, BSSs) is affected by the presence of a population of heavy dark remnants (as neutron stars and black holes). To this end, clusters characterized by different initial concentrations and different fractions of dark remnants have been modeled. We find that an increasing fraction of stellar-mass black holes significantly delays the mass segregation of BSSs and the visible stellar component. In order to trace the evolution of BSS segregation, we introduce a new parameter ($A^+$) that can be easily measured when the cumulative radial distribution of these stars and a reference population are available. Our simulations show that $A^+$ might also be used as an approximate indicator of the time remaining to the core collapse of the visible component.