The Building Blocks of Galactic Chemical Evolution
Impact of rotation and convective boundary mixing in low mass AGB stars
Jacqueline den Hartogh
Umberto Battino (Basel), Raphael Hirschi (Keele, Kavli IPMU (WPI)), Falk Herwig (University of Victoria, JINA), Marco Pignatari (University of Hull,Konkoly Observatory), and NuGrid collaboration
Keele University
After the central He burning in exhausted, stars with an initial mass of 1.5-3 solar masses start the AGB phase. In this phase, the s-process takes place, which is producing about half of all elements heavier than iron. Our non-rotating AGB stellar models calculated with MESA (see Battino et al., submitted) include a treatment of convective boundary mixing based on the results of hydrodynamic simulations and on the theory of mixing due to gravity waves in the vicinity of convective boundaries. We show examples of how the models compare with spectroscopic abundance observations and presolar grains measurements. In particular, our models reproduce the highest observed values of the s-process index [hs/ls]. On the other hand, the full range of the observed [hs/ls] as well as the laboratory measurement of Zr isotopic-ratios were not properly reproduced. A spread of initial rotational velocity in AGB stars might help to improve this. We are calculating stellar evolution models including both rotation and the above described ingredients, enabling us to analyse their interplay and the impact on s-process efficiencies.
09:00 - 10:30
EX - LT1 (100)