Nucleosynthesis in AGB stars (Amanda Karakas, Australian National University)

The asymptotic giant branch (AGB) is the last nuclear-burning phase for stars with initial masses between about 0.8 to 8 solar masses. The nucleosynthesis is driven by thermal instabilities of the helium-burning shell, the products of which are dredged to the stellar surface by recurrent mixing episodes (the third dredge-up). Hot bottom burning (HBB) occurs in intermediate-mass AGB stars, over about 4 solar masses, and alters the surface composition via proton capture nucleosynthesis.  AGB stars are important dust producers in galaxies and important for the chemical evolution, although on longer timescales than core collapse supernovae. In this talk I review theoretical predictions of nucleosynthesis in AGB stars including the production of carbon, nitrogen, and heavy elements produced via neutron-capture nucleosynthesis. I will use the results of my theoretical predictions to discuss the origin of the abundance anomalies and heavy elements in globular cluster stars.