Speaker
Dr
Pavel Denisenkov
(University of Victoria, Canada)
Description
I will present new results of our numerical simulations of i-process nucleosynthesis
on both single white dwarfs and rapidly accreting white dwarfs in close binary systems.
The i process occurs when convection driven by a He-shell flash ingests H from its
surrounding H-rich layer. Contrary to the case of H-ingestion in single stars (such
as the post-AGB star Sakurai's object or low-Z AGB stars), we find, based on both stellar evolution and 3D hydrodynamic simulations, that in rapidly accreting white dwarfs the H-ingestion may proceed without a catastrophic global, non-radial oscillation. The i-process nucleosynthesis depends on the H-ingestion rate and its duration. This results in different final distributions of i-process yields, some of which are similar to those observed in Sakurai's object, while the others closely resemble the abundance patterns in the CEMP-r/s stars. I will also discuss how the calculated i-process yields are affected by neutron-capture
reaction rate uncertainties of unstable isotopes and the best method of their analysis.
Finally, our new models suggest that the single-degenerate white dwarf accretion pathway
to SN Ia explosion is unlikely for most cases due to the low or even negative mass retention efficiency.
Primary author
Dr
Pavel Denisenkov
(University of Victoria, Canada)
Co-authors
Dr
Artemis Spyrou
(JINA-CEE, MSU)
Mr
Christian Ritter
(University of Victoria)
Prof.
Falk Herwig
(University of Victoria)
Dr
Georgios Perdikakis
(JINA-CEE, CMU)
Prof.
Hendrik Schatz
(JINA-CEE, MSU)
Dr
Marco Pignatari
(Hull University, UK)
Prof.
Paul Woodward
(Minnesota Institute for Astrophysics)
Dr
Robert Andrassy
(University of Victoria)
Dr
Samuel Jones
(HITS)
Mr
Stylianos Nikas
(JINA-CEE, CMU)
Dr
Umberto Battino
(Basel University)