General relativistic treatment of $f$-mode oscillations of hyperonic stars

TL;DR

This study analyzes $f$-mode oscillations in hyperonic neutron stars using full general relativity, revealing significant differences from the Cowling approximation and providing updated empirical relations for gravitational wave detection.

Contribution

It extends previous Cowling approximation results to linearized general relativity, offering more accurate $f$-mode frequency and damping time estimates for hyperonic stars.

Findings

Cowling approximation overestimates $f$-mode frequency by up to 30%.

Derived empirical relations for gravitational wave asteroseismology.

Estimated detectability of $f$-modes in gravitational wave signals.

Abstract

We present a systematic study of $f$-mode oscillations in neutron stars containing hyperons, extending recent results obtained within the Cowling approximation to linearized General Relativity. Employing a relativistic mean field model, we find that the Cowling approximation can overestimate the quadrupolar $f$-mode frequency of neutron stars by up to 30\% compared to the frequency obtained in the linearized general relativistic formalism. Imposing current astrophysical constraints, we derive updated empirical relations for gravitational wave asteroseismology. The frequency and damping time of quadrupole $f$-mode oscillations of hyperonic stars are found to be in the range of 1.47 - 2.45kHz and 0.13 - 0.51 sec respectively. Our correlation studies demonstrate that among the various parameters of the nucleonic and hyperonic sectors of the model, the nucleon effective mass shows the strongest correlation with mode characteristics and neutron star observables. Estimates for the detectability of $f$-modes in a transient burst of gravitational waves from isolated hyperonic stars is also provided.