Institute for Advanced Study Astrophysics Seminar

Rapid neutron capture (r-process) nucleosynthesis is responsible for the production of roughly half of the elements in the Periodic Table more massive than Iron. The unusual conditions needed for a successful r-process, in particular the requisite high flux of (unstable) free neutrons, have made the astrophysical site(s) in which the r-process occurs an enduring mystery. Observations of the first detected neutron star merger, GW170817, in both electromagnetic and gravitational radiation yielded evidence that merging neutron stars, long favored theoretically as r-process sources, did indeed undergo heavy element nucleosynthesis. However, these same observations suggested that neutron star mergers may not be unique in their ability to produce r-process elements. I will review recent progress on understanding r-process sources, including clues from numerical relativity simulations and observations of galactic chemical enrichment. I will then discuss how models and observations radiation from explosive astrophysical transients may reveal the origin of the heaviest elements in the Universe.