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Element Abundance Ratios in Galactic Bulge Stars

Published online by Cambridge University Press:  14 August 2015

R. Michael Rich
R. Michael Rich*
Affiliation:
Department of Astronomy, Columbia University Mail Code 5212, New York, NY, 10027

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I review the current status of measurements of element ratios in metal rich stars. These include giants in the Galactic bulge, metal rich Galactic globular clusters, and high velocity dwarfs in the Solar vicinity. There is evidence for enhancement of Mg and Ti in the bulge. While s-process elements have Solar abundance in bulge giants, they are deficient in the metal rich, high velocity dwarfs. There are no secure measurements of oxygen abundance in the bulge, but present data indicate no evidence either for extremely low or high [O/Fe] in bulge giants. The current data are limited by resolution and S/N, and I outline goals for observations with the next generation of ground-based telescopes.

If the central bulge of the Milky Way formed rapidly, one would expect that enrichment could occur only through massive star SNe, with little or no contribution from core deflagration SNe. In this scenario, one expects alpha-capture elements to be enhanced at a given [Fe/H] compared to the Solar vicinity: element abundance ratios may record something of the history of star formation. The idea is developed in Wheeler, Sneden & Truran (1989) and its application to bulges and elliptical galaxies is developed in Matteucci & Brocato (1990). As Kraft reviews in this volume, the stellar evolution effects that modify surface abundances in globular cluster stars do not appear to be a problem for field giants.

Type
II. Joint Discussions
Information
Highlights of Astronomy , Volume 11 , Issue 1: Highlights of Astronomy. As presented at the XXIIIrd General Assembly of the IAU (Part A), 1997 , 1998 , pp. 66 - 69
Copyright
Copyright © Kluwer 1998

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