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

Abstract

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 p1-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 neutron stars. Our study shows strong correlations between the frequencies of f -and p1-modes and their damping times with the pressure of β-equilibrated matter at densities equal to or slightly higher than the nuclear saturation density ρ0. Such correlations are found to be almost independent of the composition of the stars. The frequency of the p1-mode of 1.4M star is strongly correlated with the slope of the symmetry energy L0 and β-equilibrated pressure at density ρ0. 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 p1-mode is better than 15% for neutron stars of maximum mass, and improves for lower masses and higher number of radial nodes.

Investigating dark matter-admixed neutron stars with NITR equation of state in light of PSR J0952-0607

“…[87,88]. The nonradial f -mode frequency can be determined using the Cowling approximation [89][90][91][92].…”

The impact of anisotropy on neutron star properties: insights from 𝖨–𝖿–𝖢 universal relations

“…Neutron stars (NSs) exhibit oscillations that are regarded as potential sources of GWs, manifesting in various forms including radial [8][9][10][11][12][13] and non-radial [14][15][16][17] modes. When a NS experiences external or internal disturbances, it emits GWs through different oscillation modes known as quasi-normal modes (QNMs), each characterized by the restoring force that brings them back to their equilibrium state.…”

“…When a NS experiences external or internal disturbances, it emits GWs through different oscillation modes known as quasi-normal modes (QNMs), each characterized by the restoring force that brings them back to their equilibrium state. Notable QNMs include the fundamental mode (f -mode) [18][19][20], pressure mode (p-mode) [15,21], gravity mode (g-mode) [22][23][24][25][26][27][28][29], rotational mode (r-mode) [30][31][32][33][34][35], space-time mode (w-mode) [36,37], and other modes [38][39][40][41]. The frequencies of these oscillations are directly linked to the internal structure and composition of the stars [24].…”

“…In this study, we introduce the I-f -C URs for anisotropic NSs for the first time, utilizing a range of models describing unified EOSs such as RMF models (for npeµ, hyperonic npeµY, and strange npeµYs matter), density-dependent RMF models, and Skyrme-Hartree-Fock (SHF) models [15,[96][97][98][99][100][101][102]. The unified EOSs closely reproduce the properties of finite nuclei, nuclear matter, and NSs and support ≥ 2.0 M ⊙ star.…”

Probing the impact of delta-baryons on nuclear matter and non-radial oscillations in neutron stars

“…Radial oscillations involve expansions and contractions akin to a pulsating motion that helps maintain the star's spherical shape [17][18][19][20][21]. In contrast, non-radial oscillations manifest as asymmetric vibrations centered around the star's core are guided by a restoring force that brings the star back to its equilibrium state [9][10][11][22][23][24][25][26][27]. Non-radial oscillations can manifest in various modes, denoted as f , p, g, r, and w-modes, although not all of them contribute to the emission of gravitational waves.…”