Nucleosynthesis in low-mass, low-metallicity AGB stars Original Research Article

The evolution of stars with masses ranging between 1 and 3M⊙, metallicity View the MathML source and He mass fraction Y = 0.24 is followed from the zero-age main sequence through core He burning up to the thermally pulsing asymptotic giant branch phase. We find that the second thermal pulse leads to the injection of protons into a flash-driven convective shell, the outer part of which reaches the lower part of the hydrogen tail. The energy produced by proton capture reactions then induces various changes in the stellar interior. The main results of this event are that the surface abundances of CNO and 7Li become highly enhanced relative to solar abundance. We describe a new production mechanism for 7Li by this phenomenon.