Physics and Astronomy Senior Undergraduate Honors Thesis Defense

Roark Habegger

“A Time-Dependent Grid for Simulations of Binary Neutron Star Merger Ejecta”

Heavy r-process elements have been observed in the spectra of binary neutron star merger ejecta, suggesting that binary neutron star mergers are sites for the r-process. The dynamical and chemical evolution of the ejecta is thought to be highly asymmetric, with possible consequences on the chemical enrichment of the ambient interstellar gas. To better understand this evolution, I performed computational hydrodynamic simulations to examine how the merger ejecta expands into the ambient interstellar medium. I implemented an expanding grid in the Athena++ magneto-hydrodynamic fluid grid solver to study the ejecta’s evolution from immediately after shock formation. This addition allows the examination of multiple stages of the ejecta’s lifetime.

This defense will be held remotely via Zoom. Please contact Roark Habegger at roarkh@live.unc.edu for details.