SPECTROSCOPIC OBSERVATIONS OF AB-SUPERGIANTS IN M-31 AND M-33

We have observed a number of the most luminous A and B supergiants in the galaxies M 31 and M 33 at intermediate dispersion obtaining both b lue and red spectrograms. We have determined spectral types and lumino sity classifications from these data, in a few cases revising previous evaluations. From comparison with galactic analogues we estimate appr oximate metallicities for M 31 and M 33. In addition, for the first ti me we present H(alpha) profiles for these stars which we use to estima te mass loss rates. We conclude that M 31 is comparable in metallicity to our galaxy but M 33 is slightly deficient, more precise estimates requiring higher resolution data. The H(alpha) data are morphologicall y similar to those of galactic stars and clearly contradict claims tha t mass-loss rates for luminous stars in M 31 are up to a factor of ten less than their galactic counterparts. We note in particular that the M 31 star 40-1939 is confirmed here as a B1 Ia+ hypergiant rather tha n an O6 I supergiant (Hutchings et al. 1987) thus explaining the absen ce of typical wind features associated with an 06 classification. Also of particular interest are the luminous A-hypergiants in M 33, B324 e specially appears to be more luminous than any comparable star in our galaxy or the Magellanic Clouds, has an H(alpha) equivalent width of 4 0 angstrom in emission and exhibits a number of Fe II P-Cygni profiles .