Massive stars in nearby galaxies

Classifications are derived using a machine-learning model developed in our previous work. We report classifications for 1147650 sources, with 276657 sources (~24%) being robust. Among these are 120479 Red Supergiants (RSGs; ~11%).

The classifier performs well even at low metallicities (~0.1Z_{sun}_) and distances under 1.5Mpc, with a slight decrease in accuracy beyond ~3Mpc due to Spitzer 's resolution limits. We also identified 21 luminous RSGs (log(L/L_{sun}_)>=5.5), 159 dusty Yellow Hypergiants in M31 and M33, as well as 6 extreme RSGs (log(L/L_{sun}_)>=6) in M31, challenging observed luminosity limits. Class trends with metallicity align with expectations, though biases exist.

This catalog serves as a valuable resource for individual-object studies and James Webb Space Telescope target selection. It enables follow-up on luminous RSGs and Yellow Hypergiants to refine our understanding of their evolutionary pathways. Additionally, we provide the largest spectroscopically confirmed catalog of extragalactic massive stars and candidates to date, beyond the Clouds, comprising 5273 sources (including ~330 other objects).