We report the discovery of two Li-rich giant stars ( fainter than the red giant branch bump ) in the stellar system Omega Centauri using GIRAFFE-FLAMES spectra .
These two stars have A ( Li ) =1.65 and 2.40 dex and they belong to the main population of the system ( [ Fe/H ] =–1.70 and –1.82 , respectively ) .
The most Li-rich of them ( # 25664 ) has [ Na/Fe ] =+0.87 dex that is \sim 0.5 dex higher than those measured in the most Na-rich stars of Omega Centauri of similar metallicity .
The chemical abundances of Li and Na in # 25664 can be qualitatively explained by deep extra mixing efficient within the star during its RGB evolution or by super-asymptotic giant branch ( AGB ) stars with masses between \sim 7 and 8 M _ { \odot } .
In the latter scenario , this Li-Na-rich star could be formed from the pure ejecta of super-AGB stars before the dilution with pristine material occurs , or , alternatively , be part of a binary system and experienced mass transfer from the companion when this latter evolved through the super-AGB phase .
In both these cases , the chemical composition of this unique object could allow to look for the first time at the chemical composition of the gas processed in the interior of super-AGB stars .