Non-linear radial oscillations of neutron stars: Mode-coupling results

TL;DR

This paper investigates non-linear radial oscillations in neutron stars, demonstrating mode coupling and energy transfer through numerical simulations, which advances understanding of their complex oscillation behaviour.

Contribution

It introduces a novel approach focusing on the non-linear evolution of deviations from equilibrium to study neutron star oscillations.

Findings

Quadratic and higher order mode coupling observed

Non-linear energy transfer between modes demonstrated

Feasibility of the deviation evolution approach confirmed

Abstract

The non-linear behaviour of oscillation modes in compact stars is a topic of considerable current interest. Accurate numerical studies of such phenomena are likely to require powerful new approaches to both fluid and spacetime computations. We propose that a key ingredient of such methods will be the non-linear evolution of deviations from the background stationary equilibrium star. We investigate the feasibility of this approach by applying it to non-linear radial oscillations of a neutron star, and explore numerically various non-linear features of this problem, for a large range of amplitudes. Quadratic and higher order mode coupling and non-linear transfer of energy is demonstrated and analysed in detail.