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O. Vargas-Ferro, V.V. Smith (University of Texas at El Paso), D.L. Lambert (University of Texas at Austin), L.M. Hobbs (University of Chicago)
Lithium abundances are presented for a sample of 23 halo dwarf and subgiant stars. The abundances are derived from high signal-to-noise (S/N ~ 400), high-resolution (R = 120,000) spectra obtained at McDonald Observatory. The program stars span the metallicity range of [Fe/H] = -3.0 to -1.0 and abundances ( or upper limits) are also determined for the minor isotope 6Li. The 6Li abundances are used to constrain possible stellar mixing and Li destruction, as well as the contribution to the lithium abundance from cosmic-ray synthesis. The primordial lithium abundance is estimated by an extrapolation to zero Fe abundance.
This research is supported, by part, by the Texas Advanced Research Program (003661-0003-1999) and the National Science Foundation (AST99-87374).