Characteristics of Yellow Supergiants in the Michigan Spectral Catalogue

One of the rarest types of stars classified by Nancy Houk in her Michigan Spectral Catalogue are the yellow supergiants. Over 161,000 stars were catalogued visually using 10° objective-prism plates (2 Å resolution), but only 29 F and 15 G stars were assigned luminosity classes of Ia, Ia/ab, Iab, and Iab/b. For this investigation, the corresponding Tycho magnitudes and Gaia distances, along with other previously published observations, have been used to focus on the temperatures, luminosities, absolute bolometric magnitudes, B-V color indices, radii, distances, and Galactic (l, b) distributions of these stars. These characteristics have been used to study the yellow supergiants both as individuals and as a group, and they are presented via a variety of graphs, including H-R diagrams and Galactic distribution plots. We trust our findings will inspire others to further study these unique stars.