Chemical characterization of three Li-rich stars with high-resolution spectroscopy

Li-rich stars are a class of rare stars presenting a surface lithium abundance that exceeds that of other stars in the same evolutionary stage. The origin of these objects is still debated: the proposed Li enrichment routes involve the Cameron-Fowler mechanism, the mass transfer process in binary systems or the engulfment of sub stellar bodies. Two important diagnostics are multi-epoch RV measurements and the search for chemical signatures that may reveal anomalous enrichment, such as that resulting from material processed in massive AGB stars and subsequently transferred onto the observed star. To date, a comprehensive chemical analysis covering different groups of elements has been performed for only a small number of metal-poor Li-rich stars, while for many Li-rich stars only a limited and heterogeneous set of elemental abundances has been reported. This work represents a first step towards a systematic chemical characterization of Li-rich stars, with the aim of shedding light on their possible formation channels. We present the chemical analysis of three metal-poor Li-rich stars. No radial velocity variability was detected over a baseline of six years for Star 1, and over a baseline of 14 years for Star 2 and Star 3, as all three stars display radial velocities values agreeing with those reported by literature. The non detection of radial velocity variability disfavours binary systems. The derived Li abundances are overall in good agreement with literature, confirming the targets as Li-rich stars. We derived for all the targets the chemical abundances of several elements. We confirmed the metal poor nature of the three stars. The targets show compatible chemical patterns typical of metal-poor Galactic field stars. The only peculiar abundance is found in Star 1 that exhibits a high Na abundance.