The properties of neutron and strange matter stars are discussed from global and observational perspectives. The global features, i.e., the mass-radius relation, the moment of inertia, and the binding energy, of these objects can be understood by examination of the few known relevant analytic solutions to Einstein's equations. A close connection exists between neutron star radii and the density dependence of the isospin dependence of strong interactions, i.e., the nuclear symmetry energy. Interestingly, a similar relation has been found to exist between the symmetry energy and the neutron skin thickness of neutron-rich nuclei, the object of a new generation of laboratory experiments, although these are 1018 times smaller. Recent observations of neutron star masses and radiation radii are summarized. The status of these observations as predictors of nuclear force properties is examined. The combination of observations, laboratory experiments, and theory is an extremely powerful tool for both nuclear physics and nuclear astrophysics.
Fusion in Space: Nuclear Astrophysics, Neutron Star Mergers, and Accretion Disks
