(Fe) = 7.51 ±
0.01 dex. The average values of [Fe/H] in the solar neighborhood, the
halo, and Galactic bulge are -0.2, -1.6, and -0.2 dex respectively.
| Annu. Rev. Astron. Astrophys. 1997. 35:
503-556 Copyright © 1997 by . All rights reserved |
Reprinted with kind permission from , 4139 El Camino Way, Palo Alto, California, USA
For a PDF version of the article, click here.
Abstract. The metallicity of stars in the Galaxy ranges from
[Fe/H] = -4 to +0.5 dex, and the solar iron abundance is
(Fe) = 7.51 ±
0.01 dex. The average values of [Fe/H] in the solar neighborhood, the
halo, and Galactic bulge are -0.2, -1.6, and -0.2 dex respectively.
Detailed abundance analysis reveals that the Galactic disk, halo, and bulge exhibit unique abundance patterns of O, Mg, Si, Ca, and Ti and neutron-capture elements. These signatures show that environment plays an important role in chemical evolution and that supernovae come in many flavors with a range of element yields.
The 300-fold dispersion in heavy element
abundances of the most metal-poor stars suggests incomplete mixing of ejecta
from individual supernova, with vastly different yields, in clouds of ~
106
M
.
The composition of Orion association stars indicates that star-forming regions are significantly self-enriched on time scales of 80 million years. The rapid self-enrichment and inhomogeneous chemical evolution models are required to match observed abundance trends and the dispersion in the age-metallicity relation.
Key words: abundances, chemical composition, the Galaxy, nucleosynthesis, stars
Table of Contents
INTRODUCTION
THE SOLAR IRON ABUNDANCE
SUPER METAL-RICH STARS
OBSERVED METALLICITY DISTRIBUTION FUNCTION
The Disk
The Halo
The Bulge
AGE-METALLICITY RELATION
ABUNDANCE TRENDS WITH METALLICITY
Alpha Elements
Disk Alpha Elements
Bulge Alpha Elements
Halo Alpha Elements
SOME LIGHT ELEMENTS
Carbon
Aluminum and Sodium
HEAVY ELEMENTS
Disk and Bulge Heavy Elements
Halo Heavy Elements
IRON-PEAK ELEMENTS
FINAL THOUGHTS
REFERENCES
