Analyzing the Upper Mass Boundary of Main Sequence of Stars

Abstract

This study explores the upper mass boundary of main sequence stars, a fundamental aspect of astrophysics that shapes our understanding of stellar evolution, galactic dynamics, and cosmic chemical enrichment. The maximum stellar mass is not a fixed limit but depends on various factors, including stellar winds, metallicity, and the properties of molecular clouds. Historical estimates range from 120 to 300 solar masses, reflecting the intricate interplay of environmental conditions and initial formation parameters. Massive star formation begins with the gravitational collapse of gas clumps within giant molecular clouds, leading to protostar formation. This early stage involves non-homologous collapse, heavily influenced by magnetic fields and accretion dynamics. As mass accumulates, radiation-driven winds shape the surrounding medium, ultimately determining whether the star will reach supernova or collapse into a black hole. This research critically examines key formation mechanisms—monolithic collapse, competitive accretion, and stellar mergers—each governed by interstellar medium (ISM) properties. Through analysis of contemporary simulations and observational data, the study aims to refine our understanding of the factors regulating high-mass star formation and their implications for the initial mass function (IMF). It also investigates the balance between mass accretion and stellar winds, which can limit a star’s growth, as well as the role of metallicity in influencing radiation pressure and the upper mass boundary. Ultimately, this study underscores the complexity of high-mass star formation and its pivotal role in cosmic evolution, highlighting the need for further research to unravel the mechanisms governing stellar mass limits.