The Massive Star Population in M101. III. Spectra and Photometry of the Luminous and Variable Stars

Understand

We discuss moderate resolution spectra, multicolor photometry, and light curves of thirty-one of the most luminous stars and variables in the giant spiral M101.

• The majority are intermediate A to F-type supergiants.
• We present new photometry and light curves for three known "irregular blue variables" V2, V4 and V9) and identify a new candidate.
• Their spectra and variability confirm that they are LBV candidates and V9 may be in an LBV-like maximum light state or eruption.