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Description
We present chemical abundances for 110 stars identified in objective-prism surveys as candidates for being very metal-poor. The abundances are derived from high-S/N, intermediate-resolution spectra obtained with the Keck Observatory Echellette Spectrograph and Imager (ESI). An additional 25 stars with well-determined abundances ranging from [Fe/H]=-1.5 to -3.2 were observed and the results used to help calibrate our analysis and determine the accuracy of our abundance determinations. Abundances for the program stars were measured for Fe, Mg, Ca, Ti, Cr, and Ba with an accuracy of approximately 0.3dex. Fifty-three of the stars in our sample have [Fe/H]<=-2, 22 have [Fe/H]<=-2.5, and 13 have [Fe/H]<=-2.9. Surprisingly, approximately one-third of the sample is relatively metal-rich, with [Fe/H]>-1.5. In addition to identifying a number of extremely metal-poor stars, this study also shows that moderate-resolution spectra obtained with the Keck ESI yield relatively accurate abundances for stars as faint as V=14 with modest exposure time (~20 minutes). This capability will prove useful if the so-far elusive stars at [Fe/H]<-4 turn out to be mostly fainter than V=15.
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