| Issue |
EAS Publications Series
Volume 48, 2011
CRAL-2010 A Universe of Dwarf Galaxies
|
|
|---|---|---|
| Page(s) | 19 - 25 | |
| Section | First Stars | |
| DOI | https://doi.org/10.1051/eas/1148003 | |
| Published online | 11 July 2011 | |
M. Koleva, Ph. Prugniel and I. Vauglin (eds)
EAS Publications Series, 48 (2011) 19–25
The Elemental Abundance Distributions of Milky Way Satellite Galaxies
Hubble Fellow, California Institute of Technology, Department of Astronomy, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125, USA
e-mail: enk@astro.caltech.edu
The chemical compositions of the stars in Milky Way (MW) satellite galaxies reveals the history of gas flows and star formation (SF) intensity. This talk presented a Keck/DEIMOS spectroscopic survey of the Fe, Mg, Si, Ca, and Ti abundances of nearly 3000 red giants in eight MW dwarf satellites. The metallicity and alpha-to-iron ratio distributions obey the following trends: (1) The more luminous galaxies are more metal-rich, indicating that they retained gas more efficiently than the less luminous galaxies. (2) The shapes of the metallicity distributions of the more luminous galaxies require gas infall during their SF lifetimes. (3) At [Fe/H]< −1.5, [α/Fe] falls monotonically with increasing [Fe/H] in all MW satellites. One interpretation of these trends is that the SF timescale in any MW satellite is long enough that Type Ia supernovae exploded for nearly the entire SF lifetime.
© EAS, EDP Sciences, 2011