Share Email Print

Proceedings Paper

Abundances of stars in the galactic bulge obtained using the Keck Telescope
Author(s): R. Michael Rich; Andrew McWilliam
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

We report on the detailed abundances of giants in the Galactic bulge, measured with the HIRES echelle spectrograph on the 10-m Keck telescope. We also review other work on the bulge field population and globular clusters using Keck/HIRES. Our new spectra have 3 times the resolution and higher S/N than previous spectra obtained with 4m telescopes. We are able to derive log g from Fe II lines and excitation temperature from Fe I lines, and do not rely on photometric estimates for these parameters. We confirm that the iron abundance range extends from -1.6 to +0.55 dex. The improved resolution and S/N of the Keck spectra give (Fe/H) typically 0.1 to 0.2 dex higher than previous studies, for bulge stars more metal rich than the Sun. Alpha elements are enhanced even for stars at the Solar metallicity. We confirm our earlier abundance analysis of bulge giants and find that Mg and Ti are enhanced relative to Ca and Si even up to (Fe/H) equals +0.55. We also report the first reliable estimates the bulge oxygen abundance. Our element ratios confirm that bulge giants have a clearly identifiable chemical signature, and suggest a rapid formation timescale for the bulge.

Paper Details

Date Published: 29 June 2000
PDF: 12 pages
Proc. SPIE 4005, Discoveries and Research Prospects from 8- to 10-Meter-Class Telescopes, (29 June 2000); doi: 10.1117/12.390138
Show Author Affiliations
R. Michael Rich, Univ. of California/Los Angeles (United States)
Andrew McWilliam, Observatories of the Carnegie Institution of Washington (United States)

Published in SPIE Proceedings Vol. 4005:
Discoveries and Research Prospects from 8- to 10-Meter-Class Telescopes
Jacqueline Bergeron, Editor(s)

© SPIE. Terms of Use
Back to Top