1999A&A...352..117R

The evolution of the ⁷Li abundance in the Galaxy has been computed by means of the two-infall model of Galactic chemical evolution. We took into account several stellar ⁷Li sources: novae, massive AGB stars, C-stars and Type II SNe. In particular, we adopted new theoretical yields for novae. We also took into account the ⁷Li production from GCRs. In particular, the absolute yields of ⁷Li, as suggested by a recent reevaluation of the contribution of GCR spallation to the ⁷Li abundance, have been adopted. We compared our theoretical predictions for the evolution of ⁷Li abundance in the solar neighborhood with a new compilation of data, where we identified the population membership of the stars on a kinematical basis. A critical analysis of extant observations revealed a possible extension of the Li plateau towards higher metallicities (up to [Fe/H]~-0.5 or even -0.3) with a steep rise afterwards. We conclude that 1) the ⁷Li contribution from novae is required in order to reproduce the shape of the growth of A(Li) versus [Fe/H], 2) the contribution from Type II SNe should be lowered by at least a factor of two, and 3) the ⁷Li production from GCRs is probably more important than previously estimated, in particular at high metallicities: by taking into account GCR nucleosynthesis we noticeably improved the predictions on the ⁷Li abundance in the presolar nebula and at the present time as inferred from measures in meteorites and T Tauri stars, respectively. We also predicted a lower limit for the present time ⁷Li abundance expected in the bulge, a prediction which might be tested by future observations.