Northwestern Events Calendar


Astro Seminar: Alexander Ji: Understanding R-Process Nucleosynthesis with Stellar Abundances and Astrophysical Transients

When: Tuesday, April 6, 2021
4:00 PM - 5:00 PM Central

Where: Online

Audience: Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Samantha Westlake  

Group: Physics and Astronomy Astrophysics Seminars

Category: Academic


Abstract: Half of the heaviest elements in the periodic table are synthesized in the rapid neutron-capture process (r-process), but the astrophysical origin of these elements has been debated for over 60 years. The current debate centers around whether r-process elements are mostly synthesized by neutron star mergers or rare core-collapse supernovae. The recent observation of a neutron star merger in both gravitational waves and electromagnetic radiation (GW170817 and its associated gamma ray burst/kilonova) did not resolve this debate, but it does emphasize the close connection between elemental abundances of stars and direct observations of astrophysical transients. In this talk, I will show two examples of how chemical abundances in old, metal-poor stars can be combined with observations of astrophysical transients to understand r-process nucleosynthesis. First, I will use abundance ratios in metal-poor stars to predict the expected composition of future kilonovae. Second, I will use long gamma ray bursts to motivate a new model for explaining r-process scatter in metal-poor stars. These examples highlight the promise of connecting stellar abundances and astrophysical transients, but I will also discuss the crucial role of early galaxy formation in making this connection.


Speaker: Alexander Ji, The University of Chicago


Host: Wen-fai Fong


If you know someone who would be interested in attending this talk, please contact Samantha Westlake ( to access the Zoom link.

Keywords: Physics, Astronomy, Astrophysics

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