Nuclear physics and the GW170817 kilonova*

Over a year ago we celebrated the incredible discovery of a neutron star merger event - GW170817 - in both gravitational and electromagnetic waves. The optical signal that accompanied GW170817 provided the first firm proof that neutron star mergers produce heavy elements. Still, it is not known exactly which elements are produced by mergers and in what proportions. Are neutron star mergers the sole astrophysical source of the heaviest elements via r-process nucleosynthesis or do other extreme events contribute? A full understanding of neutron star mergers and their role in galactic chemical evolution requires progress in a number of areas. One key area is nuclear physics. Thousands of exotic nuclear species participate in the r-process, and their properties shape abundance patterns and kilonova signals. Here we discuss how nuclear physics uncertainties influence predictions of neutron star merger nucleosynthesis observables. We will then explore the promise of experimental campaigns at rare isotope beam facilities to both reduce these uncertainties and provide insight into astrophysical environments of heavy element production.