Fusion in Space: Nuclear Astrophysics, Neutron Star Mergers, and Accretion Disks

February 14, 2025

TIME: 3:30 PM

LOCATION: GMCS 314

SPEAKER: Dr. Jonah Miller, Los Alamos National Laboratory

ABSTRACT:

In the extreme environments achievable in the core of a dying or dead star, nuclear reactions are of fundamental importance. Fusion of elements lighter than iron and the fission of unstable heavy isotopes are both deep reservoirs of energy. Moreover, understanding the nuclear reactions occurring in space helps us answer questions about our own origins by providing insight into the formation of the material of which we are composed. In this talk, I will describe two exciting topic in nuclear astrophysics: neutron star mergers and collapsars. In 2017, we observed the merger of two neutron stars, ultracompact cores of dead stars. After the merger, they probably eventually formed a torus of material orbiting around and accreting onto a central black hole. Amazingly, the collapse of a rapidly rotating massive star at the end of its life can produce a similar scenario, with some key differences. I present state-of-the-art supercomputer simulations of these accretion disk” systems, and describe how we can see these events on Earth and how they contribute to the total abundance of heavy elements in the universe.

VIDEO: