Seminaire Lagrange -- Daisuke Tanaguchi (NAOJ) -- Multi-wavelength perspective on red supergiants: from stellar evolution to the Great Dimming

Multi-wavelength perspective on red supergiants: from stellar evolution to the Great Dimming

Red supergiants are a class of massive stars soon ending their lives as supernovae. Their properties, such as mass-loss rates and effective temperatures, are key to understanding both massive star evolution and the nature of resulting supernovae. Owing to their high luminosity, red supergiants also serve as useful tracers of stellar chemical abundances in the Milky Way and nearby galaxies. Multi-wavelength observations are essential to probe the different components of red supergiants and to constrain the physical parameters of these complex systems. In this talk, I will present our recent results on red supergiants, including: (1) the Great Dimming of Betelgeuse, investigated using optical/infrared photometry from the Himawari-8 meteorological satellite; and (2) accurate measurements of effective temperatures and chemical abundances of nearby red supergiants based on near-infrared high-resolution spectroscopy.