The stellar origin of 7Li - Do AGB stars contribute a substantial fraction of the local Galactic lithium abundance?

Abstract

We adopt up-to-date 7Li yields from asymptotic giant branch stars in order to study the temporal evolution of 7Li in the solar neighbourhood in the context of a revised version of the two-infall model for the chemical evolution of our galaxy. We consider several lithium stellar sources besides the asymptotic giant branch stars such as Type II supernovae, novae, low-mass giants as well as Galactic cosmic rays and low-mass X-ray binaries. We conclude that asymptotic giant branch stars cannot be considered as important 7Li producers as believed in so far and that the contribution of low-mass giants and novae is necessary to reproduce the steep rise of the 7Li abundance in disk stars as well as the meteoritic 7Li abundance. Lithium production in low-mass X-ray binaries hardly affects the temporal evolution of 7Li in the solar neighbourhood.

11 pages, 6 figures, accepted for publication in A&A