New Lithium Measurements in Metal-Poor Stars

We provide lambda 6708 Li I measurements in 37 metal-poor stars, most of which are poorly studied or have no previous measurements, from high-resolution and high-S/N spectroscopy obtained with the McDonald Observatory 2.1 m and 2.7 m telescopes. The typical line-strength and abundance uncertainties, confirmed by the thinness of the Spite plateau manifested by our data and by comparison with previous measurements, are <= 4 m angstrom and <= 0.07-0.10 dex, respectively. Two rare moderately metal-poor solar-T-eff dwarfs, HIP 36491 and 40613, with significantly depleted but still detectable Li are identified; future light-element determinations in the more heavily depleted HIP 40613 may provide constraints on the Li depletion mechanism acting in this star. We note two moderately metal-poor and slightly evolved stars, HIP 105888 and G265-39, that appear to be analogs of the low-Li moderately metal-poor subgiant HD 201889. Preliminary abundance analysis of G265-39 finds no abnormalities that suggest that the low Li content is associated with AGB mass transfer or deep mixing and p-capture. We also detect line doubling in HIP 4754, heretofore classified as SB1.