The luminosity of red supergiants in the andromeda galaxy

A blink survey of M31 undertaken by means ofB andV plates taken at the 2 m Rozhen observatory telescope gave the possibility to select ten brightest red supergiant candidates. There are a few bright red supergiants in M31 in comparison the LMC, M33, and our Galaxy. They are more frequent in the northern part of M31 where the higher rate of star formation occurs. Our search indicatedM _V –8.0 for the brightest red supergiants. Their occurrence in a galaxy depends not only on luminosity of the latter but also on the rate of star formation in it.