The History Goes On: Century Long Study of Romano's Star

TL;DR

This study presents a comprehensive analysis of Romano's Star over a century, revealing its unique evolutionary status as a post-LBV star with detailed insights into its wind, luminosity, and circumstellar environment.

Contribution

It provides the first extensive long-term observational study of Romano's Star, linking its properties to the evolutionary path of massive stars.

Findings

Increase in bolometric luminosity during light maxima

Detailed structure and composition of stellar wind

Evolutionary implications for massive star development

Abstract

GR 290 (M 33 V0532 = Romano's Star) is a unique variable star in the M33 galaxy, which simultaneously displays variability typical for luminous blue variable (LBV) stars and physical parameters typical for nitrogen-rich Wolf-Rayet (WR) stars (WN). As of now, GR 290 is the first object which is confidently classified as a post-LBV star. In this paper, we outline the main results achieved from extensive photometric and spectroscopic observations of the star: the structure and chemical composition of its wind and its evolution over time, the systematic increase of the bolometric luminosity during the light maxima, the circumstellar environment. These results show that the current state of Romano's Star constitutes a fundamental link in the evolutionary path of very massive stars.