Axial quasinormal modes of static neutron stars in the nonminimal derivative coupling sector of Horndeski gravity: spectrum and universal relations for realistic equations of state

TL;DR

This paper investigates how a specific modified gravity theory affects the oscillation modes of neutron stars, revealing changes in their spectra and universal relations across various equations of state.

Contribution

It provides the first analysis of axial quasinormal modes in Horndeski gravity, highlighting modifications to spectra and universal relations compared to General Relativity.

Findings

Modified spectra of frequencies and damping times in Horndeski gravity

Altered universal relations between modes and stellar parameters

Differences observed across multiple equations of state

Abstract

We study axial quasinormal modes of static neutron stars in the nonminimal derivative coupling sector of Horndeski theory. We focus on the fundamental curvature mode, which we analyse for ten different equations of state with different matter content. A comparison with the results obtained in pure General Relativity reveals that, apart from modifying the spectrum of the frequencies and the damping times of the stars, this theory modifies several universal relations between the modes and physical parameters of the stars, that are otherwise matter-independent.