The University of Southampton
University of Southampton Institutional Repository

Perturbation theory for post-Newtonian neutron stars

Perturbation theory for post-Newtonian neutron stars
Perturbation theory for post-Newtonian neutron stars

Neutron stars are compact, relativistic bodies that host several extremes of modern physics. An exciting development in recent years has been the opportunity to probe this exotic physics by observing compact-binary coalescences using sensitive gravitational-wave and electromagnetic instruments. To maximise the science inferred from these measurements, we require models that accurately represent the physics. In this study, we consider the post-Newtonian approximation to general relativity for the modelling of neutron-star dynamics, with a particular view to model dynamical tides at the late stages of binary inspiral. We develop the post-Newtonian perturbation equations for a non-rotating star and show that the perturbation problem is Hermitian and therefore derives from a fundamental Lagrangian. Establishing this Lagrangian system leads to a conserved symplectic product and canonical energy for the perturbations. We determine the orthogonality condition for the post-Newtonian oscillation modes, which in turn forms the foundation of a mode-sum representation often used for dynamical tides. Finally, we demonstrate that the perturbation formulation is unique.

hydrodynamics, neutron stars, oscillations, post-Newtonian theory
0264-9381
Gittins, Fabian
657ec875-fac3-4606-9dcd-591ef22fc9f6
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Yin, Shanshan
1a1d6d2f-3b19-4ac9-9151-e496b32be131
Gittins, Fabian
657ec875-fac3-4606-9dcd-591ef22fc9f6
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Yin, Shanshan
1a1d6d2f-3b19-4ac9-9151-e496b32be131

Gittins, Fabian, Andersson, Nils and Yin, Shanshan (2025) Perturbation theory for post-Newtonian neutron stars. Classical and Quantum Gravity, 42 (13), [135014]. (doi:10.1088/1361-6382/ade83f).

Record type: Article

Abstract

Neutron stars are compact, relativistic bodies that host several extremes of modern physics. An exciting development in recent years has been the opportunity to probe this exotic physics by observing compact-binary coalescences using sensitive gravitational-wave and electromagnetic instruments. To maximise the science inferred from these measurements, we require models that accurately represent the physics. In this study, we consider the post-Newtonian approximation to general relativity for the modelling of neutron-star dynamics, with a particular view to model dynamical tides at the late stages of binary inspiral. We develop the post-Newtonian perturbation equations for a non-rotating star and show that the perturbation problem is Hermitian and therefore derives from a fundamental Lagrangian. Establishing this Lagrangian system leads to a conserved symplectic product and canonical energy for the perturbations. We determine the orthogonality condition for the post-Newtonian oscillation modes, which in turn forms the foundation of a mode-sum representation often used for dynamical tides. Finally, we demonstrate that the perturbation formulation is unique.

Text
Perturbation theory for post-Newtonian neutron stars - Accepted Manuscript
Restricted to Repository staff only until 4 July 2026.
Request a copy

More information

Accepted/In Press date: 25 June 2025
Published date: 4 July 2025
Additional Information: Publisher Copyright: © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Keywords: hydrodynamics, neutron stars, oscillations, post-Newtonian theory

Identifiers

Local EPrints ID: 503949
URI: http://eprints.soton.ac.uk/id/eprint/503949
ISSN: 0264-9381
PURE UUID: 2685edb0-2535-4d23-93d3-a6b1cf8a2fdd
ORCID for Fabian Gittins: ORCID iD orcid.org/0000-0002-9439-7701
ORCID for Nils Andersson: ORCID iD orcid.org/0000-0001-8550-3843

Catalogue record

Date deposited: 19 Aug 2025 16:31
Last modified: 21 Aug 2025 02:38

Export record

Altmetrics

Contributors

Author: Fabian Gittins ORCID iD
Author: Nils Andersson ORCID iD
Author: Shanshan Yin

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×