Lithium-rich field giants in the Sloan Digital Sky Survey

Abstract

We present a search for post-main-sequence field stars in the Galaxy with atypically large lithium abundances. Using moderate-resolution spectra taken as part of the Sloan Digital Sky Survey, along with high-resolution followup spectroscopy from the Hobby-Eberly Telescope, we identify 23 post-turnoff stars with log ε(Li) greater than 1.95, including 14 with log ε(Li) ≥ 2.3 and 8 with log ε(Li) ≥ 3.0, well above the low level expected for evolved stars. Comparison with theoretical isochrones indicates that some of our Li-rich stars are affiliated with the upper red giant branch, the asymptotic giant branch and the red clump rather than the RGB bump, which is a challenge to existing models of Li production in evolved stars. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.