Evolution of low mass population III stars from the pre-main sequence to the white dwarf cooling track

TL;DR

This paper models the evolution of low mass Population III stars from pre-main sequence to white dwarf stage, highlighting unique evolutionary features and potential observable markers of primordial star remnants.

Contribution

It provides detailed evolutionary models for primordial low mass stars and identifies markers for their potential observation and the minimum mass for Population III white dwarf progenitors.

Findings

Distinct evolutionary differences from higher metallicity stars

Initial-final mass relationship for Population III stars

Minimum mass for Population III white dwarf progenitors

Abstract

Radiation feedback from massive population III stars may have given rise to low mass star formation from primordial or nearly primordial material. If early universe low mass stars did form, some should remain locally as white dwarfs, sub-giants, or main sequence stars. In this paper, we present model calculations for the evolution of single 0.8 Msun to 3.0 Msun stars with primordial metallicity from pre-main sequence to the white dwarf cooling track, and calculations for the evolution of single 4.0 Msun to 7.0 Msun stars which conclude in the giant phase. One goal of this work is to identify potential observable markers for potential observed progenitors of first or nearly first stars. We uncover a number of seemingly peculiar evolutionary differences between that of pop III low mass stars compared with younger higher Z stars, as well as compared to other primordial evolution models. We also present an initial-final mass relationship and identify the minimum mass of a single white dwarf that could have had a population III progenitor.