The Maximum Black Hole Mass at Solar Metallicity

TL;DR

This paper investigates the maximum stellar black hole mass at solar metallicity, revealing it is around 30 solar masses due to high mass-loss rates in very massive stars, contrary to expectations that more massive stars produce more massive black holes.

Contribution

It provides a detailed analysis showing the maximum black hole mass at solar metallicity is about 30 solar masses, highlighting the impact of stellar wind mass loss on black hole formation.

Findings

Maximum black hole mass at solar metallicity is approximately 30 solar masses.

Very massive stars lose significant mass before collapsing, resulting in lighter black holes.

Counter-intuitively, more massive stars do not produce more massive black holes.

Abstract

We analyse the current knowledge and uncertainties in detailed stellar evolution and wind modelling to evaluate the mass of the most massive stellar black hole (BH) at solar metallicity. Contrary to common expectations that it is the most massive stars that produce the most massive BHs, we find that the maximum $M_{\rm BH}^{\rm Max} \simeq 30 \pm 10\,M_{\odot}$ is found in the canonical intermediate range between $M_{\rm ZAMS} \simeq 30$ and $50\,M_{\odot}$ instead. The prime reason for this seemingly counter-intuitive finding is that very massive stars (VMS) have increasingly high mass-loss rates, leading to substantial mass evaporation before they expire as stars, ending as lighter BHs than their canonical O-star counterparts.