Investigating the stellar system's life-time and the evolution of their mass function using N-body simulation

TL;DR

This study uses N-body simulations to analyze the dynamical evolution and lifetime of stellar clusters, examining single-mass and multi-mass systems, and how their mass functions change over time and with galactic position.

Contribution

It introduces modified initial parameters to establish a linear relation between cluster lifetime and relaxation time for single-mass clusters and explores mass function evolution in multi-mass clusters.

Findings

Single-mass clusters do not show a linear relation between lifetime and relaxation time.

Modified initial parameters can produce a linear relation in single-mass clusters.

Mass function slopes decrease over time, affected by galactocentric distance.

Abstract

In this thesis we study several aspects of dynamical evolution of stellar clusters. The results of more than 200 simulations of single-mass star clusters with different initial total mass, half-mass radius and galactocentric distance, are reported. Recent studies of star clusters show a linear relation between a star cluster's dissolution time and its two-body relaxation time in logarithmic scale. We found that the single-mass star clusters do not show such a linear relation. We present new modified initial parameters to obtain a linear relation for single-mass star clusters. Also the evolution of multi-mass clusters and their lifetime, in the presence of the Galaxy is investigated. We simulate about 90 multi-mass star clusters with the Nbody6 code. These clusters have different initial total mass, half-mass radius and galactocentric distance. Finally we investigate the evolution of the stellar mass function and show that the slopes of the mass functions decrease with time. In addition we study the effect of galactocentric distance of star clusters on the evolution of the mass function.