Radial pulsations of neutron stars: computing alternative polytropic models regarding density and adiabatic index

TL;DR

This paper investigates radial pulsations in neutron stars by computing four different general-relativistic polytropic models with varying definitions of density and adiabatic index, analyzing their pulsation frequencies.

Contribution

It introduces a systematic comparison of four neutron star models with different density and adiabatic index definitions, expanding understanding of pulsation behaviors.

Findings

Systematic differences in pulsation frequencies across models

Deviations exhibit consistent patterns

Comparison with previous models highlights new insights

Abstract

We revisit the problem of radial pulsations of neutron stars by computing four general-relativistic polytropic models, in which "density" and "adiabatic index" are involved with their discrete meanings: (i) "rest-mass density" or (ii) "mass-energy density" regarding the density, and (i) "constant" or (ii) "variable" regarding the adiabatic index. Considering the resulting four discrete combinations, we construct corresponding models and compute for each model the frequencies of the lowest three radial modes. Comparisons with previous results are made. The deviations of respective frequencies of the resolved models seem to exhibit a systematic behavior, an issue discussed here in detail.