Speaker
Description
Yellow Supergiants (YSGs) and Yellow Hypergaints (YHGs) represent brief and unstable phases in the lives of massive stars. They provide a link between the Red Supergiant and evolved Blue Supergiant stages, but their evolutionary pathways remain poorly constrained. Some luminous yellow stars have also been identified as Supernova progenitors. Accurate stellar parameters for YSGs and YHGs in the Milky Way are difficult to obtain due to uncertain distances caused by unreliable Gaia parallaxes for these bright, variable stars.
We present improved distance estimates for 35 of the most luminous YSGs and YHGs in the Galaxy using two independent methods: (1) Gaia astrometry combined with memberships in open clusters or OB associations, and (2) comparing stellar radial velocities with a three‑dimensional H I kinematic map of the Galaxy. The methods show good agreement, allowing us to refine distances for 28 stars. For six stars, we obtained only H I–based distances, while one object remains unconstrained.
By combining our distance estimates with literature angular diameters and effective temperatures, we derived homogeneous luminosities for a subset of 20 stars. This work is a step toward homogeneous population-level studies of YSGs and YHGs in the Milky Way.