The evolution of the binary population in globular clusters: a full analytical computation

TL;DR

This paper introduces a simplified analytical model to simulate the evolution of binary star populations in globular clusters, accounting for formation and destruction mechanisms, and compares results with observational data.

Contribution

It provides a new analytical approach to model binary evolution in globular clusters, explaining discrepancies between different simulation methods.

Findings

Binary fraction varies by a factor of 1-5 depending on initial conditions.

Binary ionization and evaporation dominate binary survival.

Significant initial binary content variations likely exist among clusters.

Abstract

I present a simplified analytical model that simulates the evolution of the binary population in a dynamically evolving globular cluster. A number of simulations have been run spanning a wide range in initial cluster and environmental conditions by taking into account the main mechanisms of formation and destruction of binary systems. Following this approach, I investigate the evolution of the fraction, the radial distribution, the distribution of mass ratios and periods of the binary population. According to these simulations, the fraction of surviving binaries appears to be dominated by the processes of binary ionization and evaporation. In particular, the frequency of binary systems changes by a factor 1-5 depending on the initial conditions and on the assumed initial distribution of periods. The comparison with the existing estimates of binary fractions in Galactic globular clusters suggests that significant variations in the initial binary content could exist among the analysed globular cluster. This model has been also used to explain the observed discrepancy found between the most recent N-body and Monte Carlo simulations in the literature.