On a couple of Lithium riddles

Abstract

Lithium is probably the only element still left without a clear origin. It is produced in the Big Bang, but the abundances in halo dwarfs do not match the predictions. A new study of the interstellar Li line in the metal poor material in the SMC provides a Li abundance close to that of the halo dwarfs, thus making stellar burning unlikely a solution of the problem. Whatever the value, a galactic Li source is then required to explain present values. ⁷ Be (that decays into ⁷ Li) has been detected in the outburst of classical novae with yields which are higher than predictions of novae explosions. Galactic chemical evolution models show that only the observational yields could make the bulk of ⁷ Li. The possible detection of the 478 Kev emission line in the V1369 Cen ([Izzo∼et∼al.(2025)]) shows consistency with the observational yields thus supporting novae as the main Li source.