Comments on the Progenitor of NGC6946-BH1

TL;DR

This paper discusses the nature of the progenitor star of NGC 6946-BH1, suggesting it was a yellow hypergiant on a post-red supergiant evolutionary track at the time of core collapse.

Contribution

It provides an analysis of the progenitor's broad-band colors to infer its evolutionary state before collapse.

Findings

Progenitor was likely a yellow hypergiant.

Star was on a post-red supergiant track.

Color analysis supports the hypergiant classification.

Abstract

The broad-band colors of the progenitor of the black hole candidate in NGC 6946 suggest that it was a yellow hypergiant on a post-red supergiant track when the core collapse occurred.