The Abundance Spread in the Boötes I Dwarf Spheroidal Galaxy
نویسندگان
چکیده
We present medium-resolution spectra of 16 radial velocity red-giant members of the low-luminosity Boötes I dwarf spheroidal (dSph) galaxy that have sufficient S/N for abundance determination, based on the strength of the Ca II K line. Assuming [Ca/Fe] ∼ 0.3, the abundance range in the sample is ∆[Fe/H] ∼ 1.7 dex, with one star having [Fe/H = –3.4. The dispersion is σ([Fe/H]) = 0.45 ± 0.08 – similar to those of the Galaxy’s more luminous dSph systems and ω Centauri. This suggests that the large mass (& 10 M⊙) normally assumed to foster self-enrichment and the production of chemical abundance spreads was provided by the non-baryonic material in Boötes I. Subject headings: galaxies: dwarf − galaxies: individual (Boötes I) − galaxies: abundances
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