Abundances and Evolution of Stars in the Bulge of the Galaxy

The heavy metal composition of the central nuclear Bulge of our Milky Way Galaxy is important to studies of the types of stars constituting both external galaxies and the first generation of stars in the disk of our Galaxy. Currently star formation is thought to proceed more rapidly in the Bulge than in the neighborhood of the Sun. A point of controversy over the last twenty years has been the question of whether strong absorption lines in the spectra of red giant stars actually reflect an enhanced abundance of heavy elements, or whether they perhaps arise as a consequence of anomalies in the structures of the atmospheres of these stars. The Principal Investigator (PI) wishes to conduct research in this area by measuring the abundance of the heavy metal elements in a selected group of Bulge red giants. This study will differ from those of the past in that high dispersion spectra will be obtained with modern solid state arrays to conduct the abundance analysis. The results will be used to estimate the mass distribution of supernovae which return nuclear-processed material into the interstellar medium. A secondary project will be to determine whether carbon-star giants (the origin of which is likewise unclear) in the Bulge have enhanced metal abundances relative to the Sun's composition.