Wolf-Rayet content of the Milky Way

TL;DR

This paper reviews the current knowledge of Wolf-Rayet stars in the Milky Way, including recent discoveries, distribution patterns, and population estimates, highlighting that the census is likely about half complete.

Contribution

It provides an updated catalog of 642 Wolf-Rayet stars, analyzes their distribution, and estimates the total population and characteristics within the Milky Way.

Findings

Current census includes 642 WR stars, likely 50% complete.

Most WR stars are not located in star clusters.

Estimated total WR population is over 1,200.

Abstract

An overview of the known Wolf-Rayet (WR) population of the Milky Way is presented, including a brief overview of historical catalogues and recent advances based on infrared photometric and spectroscopic observations resulting in the current census of 642 (v1.13 online catalogue). The observed distribution of WR stars is considered with respect to known star clusters, given that <20% of WR stars in the disk are located in clusters. WN stars outnumber WC stars at all galactocentric radii, while early-type WC stars are strongly biased against the inner Milky Way. Finally, recent estimates of the global WR population in the Milky Way are reassessed, with 1,200+/-100 estimated, such that the current census may be 50% complete. A characteristic WR lifetime of 0.25 Myr is inferred for an initial mass threshold of 25 Msun.