The mass of first stars

TL;DR

This study uses advanced 3D radiation hydrodynamics simulations to explore how primordial gas clouds form the first stars, revealing that radiative feedback limits stellar mass growth and allows for lower-mass Population III stars.

Contribution

First simulation to incorporate ultraviolet radiative feedback and 3D effects in modeling first star formation, providing new insights into stellar mass limits.

Findings

Radiative feedback significantly suppresses mass accretion onto protostars.

Five stars formed with final masses less than 60 solar masses.

Potential existence of low-mass Population III stars that could survive today.

Abstract

We perform a three dimensional radiation hydrodynamics simulation to investigate the formation of first stars from initial collapse of a primordial gas cloud to formation and growth of protostars. The simulation is integrated until 0.1 Myrs after the formation of the primary protostar by which the protostars have already settled onto main sequence stars. This is the first attempt of simulating first star formation to take into account the ultraviolet radiative feedback effect by the multiple protostars as well as the three dimensional effects such as fragmentation of the accretion disk. We find that the mass accretions onto the population III protostars are significantly suppressed by the radiative feedback from themselves. As a result, we find five stars formed in this particular simulation, and that the final mass of the stars are < 60Msun, including a star of 4.4Msun. Formation of such a star hints at the existence of even lower-mass stars that would live today.