Stellar evolution


AGB stellar evolution
Post-AGB evolution, CSPN

AGB stellar evolution

A large fraction of my work has been on the evolution and nucleosynthesis of Asymptotic Gian Branch stars. I have worked on convection induced extra-mixing and nucleosynthesis in AGB stars. The result of several years of research in this area is summarised in my 2005 ARAA article. However, it is clear that new challenges from detailed observations, including those of stars with extremely and ultra-metal poor composition, can only be met with the help from mulit-dimensional hydrodynamic simulations of the stellar interior.

Two recent papers on AGB evolution include work on hot-bottom burning and dredge-up in extremely metal-poor stars and a detailed yield and structure evolution data paper for EMP AGB stars.

Post-AGB evolution, CSPN

Central stars of Planetary Nebula come in two flavors: H-normal and H-deficient. Abnormally low H-abundance, or even the absence of H in CSPN, in the PG1159 and [WC]-type CSPN stars, has been associated with the born-again or very late He-shell flash evolution. Although the general concept of this evolution is around for some time (e.g. Iben etal, 1983) the models are only recently starting to work quantitatively. Klaus Werner (University of Tübingen, Germany) and myself have summarised the current state of the art in an invited PASP review. It seems to become clear that the burning and mixing events, which characterize this He-shell flash in hot pre-White Dwarfs require multi-dimensional simulations of reactive-convective burning and mixing as well. A list of my post-AGB papers can be found here.
Falk Herwig, Last update: Thu 19 Jan 2017 07:22:25 PST , WWW home