Nuclear astrophysics

Nuclear physics and astronomy are inextricably intertwined. In fact, more than ever, astronomical discoveries are driving the frontiers of nuclear physics while our knowledge of nuclei is driving progress in understanding the universe.

Because of its powerful technical capabilities, FRIB forges tighter links between the two disciplines. Rare isotopes and nuclear matter play a critical role in the evolution of stars and other cosmic phenomena such as novae, supernovae, and neutron start mergers, but up to now the most relevant rare isotopes have been largely out of the reach of terrestrial experiments. FRIB provides access to most of the rare isotopes important in these astrophysical processes and allow scientists to probe the properties of asymmetric nuclear matter. This will help to shed light on several intertwined, fundamental questions about our universe:

• Where do the chemical elements come from, and how do they evolve over cosmic time?
• What are the properties of neutron stars? What is the nature of matter at extreme temperatures and densities? How do neutron star mergers power gravitational wave emission and synthesize heavy elements?
• How do massive stars end their lives? How are supernovae, gamma ray bursts, novae, and X-ray bursts powered?
• How do neutrinos and neutrino masses affect element synthesis? What can neutrino observations tell us about the properties of dense matter?

Astronomical missions across the electromagnetic spectrum (including the Hubble Space Telescope, Chandra X-ray Observatory, and the Fermi Gamma-ray Space Telescope) have provided a wealth of data about element synthesis, stellar explosions, and neutron stars. Future missions such as the James Web Space Telescope and the Large Scale Synoptic Telescope will continue to provide observations of these events for the next decades.

Additionally, Advanced LIGO has recently provided a completely new window into the physics of neutron stars, gravitational waves. Neutrino experiments such as Super Kamiokande and DUNE may detect neutrinos from a core-collapse supernova in the coming decades. Therefore, there is and will continue to be a wealth of multi-messenger data coming from these events.

Interpreting these observations requires knowledge of the properties of many rare isotopes that can be studied at FRIB.

Combining the FRIB discoveries with future astronomy missions and advanced computer simulations of astrophysical sites will provide a potent and complementary set of tools to understand how the universe works.