Lithium and proton-capture elements in　globular clusters: the case of 47 Tucanae

摘要

The determination of lithium (Li) abundances in Globular Clusters (GCs), along with proton-capture elements (Na, O, Mg, Al), offer a key tool to address the pollution scenario and its mechanisms, the dilution process acting within each star and the first phases in the lifetime of GCs. We present our results on Na, O and Li abundance determination in a large sample of dwarf stars in the GC 47 Tucanae (NGC 104). While we found a clear Na-O anti-correlation, in perfect agreement with giant members by Carretta et al. (2009a,b), Li abundance appears neither positively correlated with oxygen, nor anti-correlated with sodium. Our finding unveils an intrinsic scatter in Li content, independent of intra-cluster pollution by a first generation of more massive, faster evolving stars.