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Title: The [Fe/H], [C/Fe], and [α/Fe] Distributions of the Boötes I Dwarf Spheroidal Galaxy
Authors: Lai, D. K
Lee, Y. S
Bolte, M
Lucatello, S
Beers, T. C
Johnson, J. A
Sivarani, T
Rockosi, C. M
Keywords: Galaxies: abundances;Galaxies: dwarf;Galaxies: individual (Bootes I);Stars: abundances
Issue Date: 1-Sep-2011
Publisher: IOP Publishing
Citation: The Astrophysical Journal, Vol. 738, No. 1, 51
Abstract: We present the results of a low-resolution spectral abundance study of 25 stars in the Boötes I dwarf spheroidal (dSph) galaxy. The data were obtained with the low resolution imaging spectrometer instrument at Keck Observatory and allow us to measure [Fe/H], [C/Fe], and [α/Fe] for each star. We find both a large spread in metallicity (2.1 dex in [Fe/H]) as well as a low average metallicity in this system, lang[Fe/H]rang = –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 Boötes I to analytic chemical evolution models. While the metallicity distribution function of Boötes I is best fit by an Extra Gas chemical evolution model, leaky-box models also provide reasonable fits. We also find that the [α/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 Boötes I ultra-faint dSph could have been contributors to the Galactic halo.
Description: Open Access
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Appears in Collections:IIAP Publications

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