Crustal torsional oscillations and nuclear saturation parameters

摘要

We examine crustal torsional oscillations, newly taking into account the effect of the pasta structure. Via eigenvalue analyses with various models of the equation of state of uniform nuclear matter, we find that the fundamental frequencies of such oscillations are almost independent of the incompressibility of symmetric nuclear matter (K_0), but strongly depend on the slope parameter of the nuclear symmetry energy (L). On the other hand, we also find that the frequencies of the 1st overtones depend strongly on not only L but also K_0. By comparing the resultant frequencies to the quasi-periodic oscillations observed in the giant flares, we can constrain the values of L and K_0. Furthermore, considering the constraints on K_0 obtained from the terrestrial nuclear experiments, we can successfully make a more severe constant on not only L but also the neutron star model for the SGR 1806-20.