Studies of luminous stars in nearby galaxies. II. M supergiants in the Large Magellanic Cloud.

Basic properties of the brightest red stars in the Large Magellanic Cloud (LMC) are determined from BVRI photometry of 157 red stars and spectra of 74 of the brightest red stars, including 54 confirmed supergiants. The luminosities, reddening, and colors of the M supergiants are obtained. H-R diagrams for the luminous stars of all spectral types in the LMC are provided, and general features of these diagrams are examined. The ratio of blue to red supergiants in the LMC is estimated to be 5 for distances of no more than 1 kpc from the center, 3.5 for distances of 1 to 2 kpc, 3.8 for distances of 2 to 3 kpc, and 2.3 for distances of at least 3 kpc. It is shown that the luminous red stars in the LMC and the Galaxy have essentially the same spectral characteristics and luminosities.