Temperature Effects on Core g-modes of Neutron Stars

TL;DR

This paper investigates how finite temperatures in neutron stars, especially during mergers, affect g-mode oscillations, revealing suppression in typical mass stars and support only in the most massive hot neutron stars.

Contribution

It extends previous cold neutron star g-mode models to include finite-temperature effects relevant for neutron star mergers.

Findings

G-modes are suppressed at high temperatures in canonical mass neutron stars.

Core g-modes are supported only in neutron stars with mass ≥ 2 solar masses.

Finite-temperature effects significantly alter g-mode spectra in neutron stars.

Abstract

Neutron stars provide a unique physical laboratory to study the properties of matter at high density. We study a diagnostic of the composition of high-density matter, namely, g-mode oscillations, which are driven by buoyancy forces. These oscillations can be excited by tidal forces and couple to gravitational waves. We extend prior results for the g-mode spectrum of cold neutron star matter to temperatures that are expected to be achieved in neutron star mergers using a parameterization for finite-temperature effects recently proposed by Raithel, \"Ozel and Psaltis. We find that the g-modes of canonical mass neutron stars ($\approx$1.4$M_{\odot}$) are suppressed at high temperature, and core $g$-modes are supported only in the most massive ($\geq $2$M_{\odot}$) of hot neutron stars.