Walking along Cosmic History: Metal-poor Massive Stars

TL;DR

This paper discusses the evolution and feedback of very metal-poor massive stars across cosmic history, proposing a new metallicity ladder based on observations of extremely low-metallicity galaxies.

Contribution

It introduces a new metallicity ladder from very metal-poor galaxies to better understand early Universe massive stars, surpassing the SMC standard.

Findings

Differences in evolution and feedback of low-metallicity massive stars.

Proposal of a new metallicity ladder for cosmic history.

Overview of technological needs for studying these stars.

Abstract

Multiple generations of massive stars have lived and died during Cosmic History, invigorating host galaxies with ionizing photons, kinetic energy, fresh material and stellar-size black holes. At present, massive stars in the Small Magellanic Cloud (SMC) serve as templates for low-metallicity objects in the early Universe. However, recent results have highlighted important differences in the evolution, death and feedback of massive stars with poorer metal content that better matches the extremely low metallicity of previous Cosmic epochs. This paper proposes to supersede the SMC standard with a new metallicity ladder built from very metal-poor galaxies, and provides a brief overview of the technological facilities needed to this aim.