PHYSICS AND NEUTRON-STAR INTERIORS

Conditions in neutron stars are more extreme than almost any encountered on Earth: densities exceed those of atomic nuclei, and matter has a large neutron excess. During the past quarter of a century, the challenge of understanding neutron stars has stimulated physicists to confront conditions far different from those normally encountered terrestrially. Laboratory studies have in turn yielded important input for the studies of neutron stars. We discuss a number of examples of this continuing interplay between physics and astrophysics. The first is the equation of state of dense matter, which is the basis for all theoretical models of neutron stars. The second is the composition of dense matter. This has profound influence on neutrino generating processes in neutron stars, and hence on their cooling. A third example is nuclei with a large neutron excess, such as are expected to be present in the crusts of neutron stars. Properties of similar nuclei play an important role in theories of element production.