Spectroscopy of metal-rich M31 globular clusters

Integrated CCD spectra in the 3850-4200 A region were obtained for nine metal-rich globular clusters in M31. The spectra are analyzed using the reddening-free spectral-classification system of Rose (1984). The data are combined with data obtained by Rose and Tripicco (1986) for nine metal-rich Galactic globular clusters and with spectra of 72 stars with well-determined atmospheric parameters. It is found that the 4000 A light from metal rich M31 globulars is dominated by dwarfs, while giants and dwarfs contribute equally to the light from the mean of the metal-rich Galactic globulars. The contribution of early-type stars to the 400 A light from M31 clusters is less than 5 percent in most cases. Also, the 3883 and 4216 CN bands in the M31 globulars are very strong for their integrated spectral types. The results suggest that the metal-rich M31 globular clusters are much younger than Galactic metal-rich clusters like 47 Tuc or M71. 75 references