Speaker
Mr
Christian Ritter
(University of Victoria)
Description
We propose that convective-reactive nucleosynthesis in the dynamic merger of O- and C-shell convection zones can solve the problem of galactic chemical evolution models to account for the observed abundances of odd-Z elements, such as K and Sc. We investigate the convective-reactive events of C-ingestion into O-shell convection for a range of ingestion and
burning parameters through comprehensive nucleosynthesis calculations informed by 3D hydrodynamic simulations.
We find for large entrainment rates expected during a shell merger the efficient production of odd-Z elements.
Overproduction factors of K and Sc of eight and above could explain the underproduction
in Galactic chemical evolution models compared to halo and disk stars.
These findings are in agreement with O-C shell mergers in stellar models of the JINA/NuGrid model and yield database.
Such mergers boost the production of p-process nuclei by a large factor by providing fresh seed nuclei from the C shell.
Convective-reactive nucleosynthesis also takes place in the Si-O shell merger of one of our massive star models.
It leads to the nucleosynthesis and ejection of large amounts of Fe-peak elements with an overproduction
factor of five of the odd-Z element Mn.
We expect to find abundance signatures of shell mergers in homogeneously mixed systems such as ultra-faint dwarf galaxies.
Primary author
Mr
Christian Ritter
(University of Victoria)
Co-authors
Dr
Benoit Cote
(Michigan State University / University of Victoria)
Prof.
Falk Herwig
(University of Victoria)
Prof.
Paul Woodward
(University of Minnesota)
Dr
Robert Andrassy
(University of Victoria)
Dr
Sam Jones
(Heidelberg Institute for Theoretical Studies)
Dr
marco Pignatari
(University of Hull)