A Super Lithium Rich giant in the metal-poor open cluster Berkeley 21

Abstract

We present the analysis of FEROS commissioning spectra of 3 giants in the metal poor cluster Be 21. One of the giants has an exceptionally high Li content, comparable to the original Li in the solar system. These objects are very rare (only a handful are known), and this is the first Super Lithium Rich giant (SLIR) discovered in an open cluster. The reasons for such a high Li abundance are unknown: it could be the result of a short lived internal process, or of accretion from external sources, the former being slightly more likely. From the spectra, the metal abundance is also derived for 3 giants, giving a mean of [Fe/H]=-0.54 +/- 0.2 dex, in good agreement with recent photometric estimates, but substantially higher than estimates previously obtained.