The [Fe/H], [C/Fe], and [alpha/Fe] distributions of the Bootes I Dwarf
  Spheroidal Galaxy
  We present the results of a low-resolution spectral abundance study of 25
stars in the Bootes I dwarf spheroidal (dSph) galaxy. The data were obtained
with the LRIS instrument at Keck Observatory, and allow us to measure [Fe/H],
[C/Fe], and [alpha/Fe] for each star. We find both a large spread in
metallicity (2.1 dex in [Fe/H]) as well as the low average metallicity in this
system, <[Fe/H]>=-2.59, matching previous estimates. This sample includes a
newly discovered extremely metal-poor star, with [Fe/H]=-3.8, that is one of
the most metal-poor stars yet found in a dSph. We compare the metallicity
distribution function of Bootes I to analytic chemical evolution models. While
the metallicity distribution function of Bootes I is best fit by an Extra Gas
chemical evolution model, leaky-box models also provide reasonable fits. We
also find that the [alpha/Fe] distribution and the carbon-enhanced metal-poor
fraction of our sample (12%) are reasonable matches to Galactic halo star
samples in the same metallicity range, indicating that at these low
metallicities, systems like the Bootes I ultra-faint dSph could have been
contributors to the Galactic halo.
