Radial oscillations of neutron stars within density-dependent relativistic-mean field model

TL;DR

This paper investigates neutron star radial oscillations using density-dependent relativistic mean-field models and introduces a novel finite volume method for more stable and efficient eigenfrequency calculations.

Contribution

It presents a new numerical approach (FVM) for solving oscillation eigenvalue problems in neutron stars, improving stability and efficiency over traditional methods.

Findings

Oscillation frequencies are sensitive to the EOS of the crust.

First excited state frequency correlates linearly with symmetry energy parameters.

Density dependence of symmetry energy can be constrained via oscillation observations.

Abstract

The radial oscillations of neutron stars are studied using equations of state derived from density-dependent relativistic mean-field (DDRMF) models, which effectively describe the ground-state properties of finite nuclei. A novel numerical approach, the finite volume method (FVM), is employed to solve the eigenvalue problem associated with oscillation frequencies. Compared to conventional methods such as the finite difference method and shooting method, the FVM avoids the numerical instability encountered at high frequencies with an equation of state that includes a discontinuous adiabatic index and offers greater computational efficiency. The oscillation frequencies of high-order modes exhibit a similar trend of change. The radial displacements and pressure perturbations are largely influenced by the EOSs of crust region. {The frequency of the first excited state shows a strong linear relationship with both the slope and skewness parameters of the symmetry energy.} These findings suggest that the density dependence of the symmetry energy can be constrained through observations of neutron star radial oscillation frequencies.