Impact of the equation of state on f- and p- mode oscillations of neutron stars

Athul Kunjipurayil, Tianqi Zhao, Bharat Kumar, Bijay K. Agrawal, Madappa Prakash.


We investigate the impact of the neutron-star matter equation of state on the f- and p1-mode oscillations of neutron stars obtained within the Cowling approximation and linearized general relativity. The f– and p_{1}-mode oscillation frequencies, and their damping times are calculated using representative sets of Skyrme Hartree-Fock and relativistic mean-field models, all of which reproduce nuclear systematics and support 2M_\odot neutron stars. Our study shows strong correlations between the frequencies of f– and p_{1}-modes and their damping times with the pressure of \beta-equilibrated matter at densities equal to or slightly higher than the nuclear saturation density \rho_0. Such correlations are found to be almost independent of the composition of the stars. The frequency of the p_1-mode of 1.4M_\odot star is strongly correlated with the slope of the symmetry energy L_0 and \beta-equilibrated pressure at density \rho_0. Compared to GR calculations, the error in the Cowling approximation for the f-mode is about 30% for neutron stars of low mass, whereas it decreases with increasing mass. The accuracy of the p_{1}-mode is better than 15% for neutron stars of maximum mass, and improves for lower masses and higher number of radial nodes.

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