The Neutron Star Crust: Symmetry Energy and Shear Moduli

A self-consistent model of the neutron star crust is described, including a discussion of some of the primary physics challenges: the description of low-density neutron matter and the nuclear symmetry energy. Though often used, Skyrme models fail to describe low-density neutron matter accurately. The model also shows that the nuclear symmetry energy is the most significant uncertainty in the description of the crust, and strongly controls the composition. The model is applied to the computation of the shear modulus, which is relevant for modeling the frequencies of quasi-periodic oscillations in giant flares produced by magnetars. A clear correlation between the symmetry energy and the shear modulus is elucidated.