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Paper: Metal Abundance Estimates for F- and G-Type Stars from the Edinburgh-Cape Blue Object Survey
Volume: 165, The Third Stromlo Symposium: The Galactic Halo
Page: 254
Authors: Beers, Timothy C.; Rossi, Silvia; O'Donoghue, Darragh; Kilkenny, David; Koen, Chris; Stobie, Robert S.
Abstract: The Edinburgh-Cape Blue Object Survey is an ongoing project to identify and analyse a large sample of hot stars, such as white dwarfs, subdwarf O- and B-type stars, and hot horizontal-branch stars selected on the basis of their photographic colors (down to a magnitude limit B ~18.0) over essentially the entire southern hemisphere at high Galactic latitudes. Because of errors in the photographic colors ( ~0.15 mags), stars which can be identified as metal-deficient dwarfs and giants of the halo and thick-disk populations are inadvertently included in the initial selection. Photoelectric photometry and medium-resolution spectroscopy is used to identify the primary targets of the survey and the redder ``contaminants,'' stars which often turn out to be of interest in their own right. >From the first set of the published survey results a total of 374 candidate metal-deficient stars with photoelectric colors in the range 0.3 <= B-V <= 0.9 and with available spectra have been identified. Metallicities for a portion of these stars are obtained using a recently re-calibrated CaII K-line technique. We discuss the resulting abundances, and note that some 30 of these ``contaminant'' stars exhibit abundances below feh = -2.0, and hence are valuable probes of the metallicity distribution of the lowest abundance stars in the Galaxy. One might expect that future followup of the numerous additional cool stars from the EC survey will provide a large sample of such extremely metal-deficient stars.
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