Speaker = Dr. Nan Liu of Institute for Astrophysical Research at Boston University
Host = Hendrik Schatz schatz@frib.msu.edu
When = 2025-10-22 Wednesday
Where = FRIB 1300
Please feel free to sign up below, but note that some slots may need to be re-assigned to accommodate those with a specific need to meet the speaker. If this happens, the Admin or Speaker Host will reach out to you via email.
| Start Time | End Time | Name | Building | Room |
|---|---|---|---|---|
| 09:00 | 09:30 | Hendrik Schatz | 2006 | |
| 09:30 | 10:00 | Hendrik Schatz | 2006 | |
| 10:00 | 10:30 | Hendrik Schatz | 2006 | |
| 10:30 | 11:00 | Seth Jacobson | FRIB | 2016 |
| 11:00 | 11:30 | Artemis Spyrou | FRIB | 2008 |
| 11:30 | 12:00 | Fernando Montes | FRIB | 1067 |
| 12:00 | 13:00 | Lunch with Graduate Students | FRIB | 2311 |
| 13:00 | 13:30 | George Zimba | FRIB | 2003 |
| 13:30 | 14:00 | Chris Wrede | FRIB | 2018 |
| 14:00 | 14:30 | Georgios Perdikakis | FRIB | 2062 |
| 14:30 | 15:00 | Shane Wilkins | FRIB | 2014 |
| 15:00 | 15:30 | Speaker setup | FRIB | 1300 |
| 15:30 | 16:30 | Seminar | FRIB | 1300 |
Title = Presolar Grains as Probes of Type II Supernova Nucleosynthesis
Abstract
Presolar grains, submicron- to micron-sized meteoritic particles, originate from stellar winds and the ejecta of stellar explosions, providing direct samples of stellar material. The talk will discuss how we can leverage the isotopic compositions of presolar grains to refine our understanding of physical mixing processes within stars, stellar nucleosynthesis, and dust formation. Specifically, I will focus on the unique role of presolar grains derived from Type II core-collapse supernovae (CCSNe) in constraining explosive nucleosynthesis and the dynamic mixing processes occurring during the explosion. Drawing from our recent studies, I will present new multielement isotope data for presolar CCSN silicon carbon (SiC) and silicon nitride (Si3N4) grains. Our new isotope data specifically point to the contributions of materials from distinct regions within a CCSN to the CCSN ejecta for the SiC and Si3N4 grain formation. This inferred mixing scenario, as suggested by the CCSN grain data, aligns with recent 3D hydrodynamic model simulations of CCSN explosions. The incorporation of materials from distinct supernova regions into these grains thus enables the investigation of a variety of nucleosynthesis processes, including alpha-rich freezeouts, neutrino-nucleus reactions, and neutron-burst process. For instance, our data-model comparisons suggest that the (n,γ) cross sections of 31Si reported in the JINA REACLIB database needs to be significantly increased to boost the production of 32Si during the neutron-burst process in the He/C zone during the explosion. New nuclear experiments are thus needed to test our predictions in the future.
Relevant background with commentary from Speaker