Symmetry energy in nuclei and neutron stars

The symmetry energy plays an important role in nuclear astrophysics, ranging from the structure of nuclei to gravitational collapse to neutron stars. The BBAL paper by Bethe, Brown, et al., was among the first to recognize its importance. The role of the symmetry energy has evolved since that time when it represented one of the major uncertainties in modeling the equation of state of dense nuclear matter. At present, the parameters of the nuclear symmetry energy are tightly constrained by a concordance achieved from nuclear experiment, astrophysical observations, and ab initio theoretical calculations of neutron matter.