Open clusters in 2MASS photometry II. Mass Function and Mass Segregation

TL;DR

This study analyzes the mass function and dynamical evolution of 599 open clusters using 2MASS data, revealing how cluster sizes and mass distributions change over time and establishing an empirical relation for mass function slope decline.

Contribution

It provides a comprehensive analysis of mass segregation, cluster mass, and size evolution in a large sample of open clusters, advancing understanding of their dynamical states.

Findings

Cluster sizes decrease with dynamical evolution.

Core regions evolve faster than halos, losing low-mass stars.

Mass function slope declines exponentially with evolution.

Abstract

This is a continuation of our study of open clusters based on the 2--Micron All Sky Survey photometry. Here we present the results of the mass function analysis for 599 known open clusters in the Milky Way. The main goal of this project is a study of the dynamical state of open clusters, the mass segregation effect and an estimate of the total mass and the number of cluster members. We noticed that the cluster size (core and overall radii) decreases along dynamical evolution of clusters. The cluster cores evolve faster than the halo regions and contain proportionally less low-mass stars from the beginning of the cluster dynamical evolution. We also noticed, that the star density decreases for the larger clusters. Finally, we found an empirical relation describing the exponential decrease of the mass function slope with the dynamical evolution of clusters.