[Triumf-seminars] TRIUMF Colloquium today at 14:00

[TRIUMF Seminars]

Date/Time: Thu 2014-06-12 at 14:00

Location:  Auditorium          

Speaker:   Falk Herwig (University of Victoria)

Title:     Turbulent nuclear burning and the exotic formation of heavy elements in stars

Abstract: Many aspects of how elements form and how they are mixed through convection in stars, and how these two processes interact is still poorly understood. One example is when proton-rich envelope material is ingested into the C12-rich, convective He-burning shell through turbulent entrainment. New large-scale 3-D simulations of this entrainment process at convective boundaries and the subsequent advection and nuclear reaction of protons with C12 show that the traditional spherically-symmetric modeling approach (stellar evolution) is inapprorpiate here. The coupling of turbulent convective flow and rapid nuclear energy release leads to a previously unknown global oscillation of shell H-ingestion. This is the site of the i process, an intermediate neutron-capture process that can be observed in a nearby pre-white dwarf/post-AGB star (Sakurai's object), in pre-solar meteoritic grains and - we claim - in the abundance patterns of very metal-poor stars. The investigation of the exotic properties of the i process requires presently unknown nuclear physics data of unstable isotopes.

Stimulants available 15 minutes before the talk.

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