Identifying Stars of Mass >150 Msun from Their Eclipse by a Binary Companion

TL;DR

This study explores the existence of stars exceeding 150 solar masses in young clusters, proposing that their eclipses could reveal their presence and inform about supernovae and black hole formation.

Contribution

It identifies candidate clusters with potential stars over 150 Msun and assesses the detectability of their eclipses at extragalactic distances.

Findings

Probability of eclipsing binaries >30%

Eclipses detectable at 3 Mpc despite background light

Potential progenitors of supernovae and black holes

Abstract

We examine the possibility that very massive stars greatly exceeding the commonly adopted stellar mass limit of 150 Msun may be present in young star clusters in the local universe. We identify ten candidate clusters, some of which may host stars with masses up to 600 Msun formed via runaway collisions. We estimate the probabilities of these very massive stars being in eclipsing binaries to be >30%. Although most of these systems cannot be resolved at present, their transits can be detected at distances of 3 Mpc even under the contamination of the background cluster light, due to the large associated luminosities ~10^7 Lsun and mean transit depths of ~10^6 Lsun. Discovery of very massive eclipsing binaries would flag possible progenitors of pair-instability supernovae and intermediate-mass black holes.