Massive stars in their death-throes

TL;DR

This paper reviews recent progress in identifying supernova progenitors, highlighting key discoveries, contradictions with existing theories, and the implications for understanding massive star evolution and supernova mechanisms.

Contribution

It summarizes the current state of supernova progenitor detection, emphasizing new findings that challenge existing stellar evolution models and suggesting the need for updated theories.

Findings

Type IIP supernova progenitors are red supergiants as predicted.

No progenitors detected for hydrogen-free Type Ib/c supernovae, contrary to expectations.

Luminous blue variables may directly explode as supernovae, challenging current models.

Abstract

The study of the stars that explode as supernovae used to be a forensic study, working backwards from the remnants of the star. This changed in 1987 when the first progenitor star was identified in pre-explosion images. Currently there are 8 detected progenitors with another 21 non-detections, for which only a limit on the pre-explosion luminosity can be placed. This new avenue of supernova research has led to many interesting conclusions, most importantly that the progenitors of the most common supernovae, type IIP, are red supergiants as theory has long predicted. However no progenitors have been detected thus far for the hydrogen-free type Ib/c supernovae which, given the expected progenitors, is an unlikely result. Also observations have begun to show evidence that luminous blue variables, which are among the most massive stars, may directly explode as supernovae. These results contradict current stellar evolution theory. This suggests that we may need to update our understanding.