Radial oscillations of neutron stars in Starobinsky gravity and its Gauss-Bonnet extension

Fuente: arXiv
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Main Authors: Li, Ziyi, Yu, Zhong-Xi, Luo, Zhe, Li, Shoulong, Yu, Hongwei
Format: Preprint
Published: 2025
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author Li, Ziyi
Yu, Zhong-Xi
Luo, Zhe
Li, Shoulong
Yu, Hongwei
author_facet Li, Ziyi
Yu, Zhong-Xi
Luo, Zhe
Li, Shoulong
Yu, Hongwei
contents Starobinsky gravity, as one of the simplest and best-behaved higher-curvature gravity theories, has been extensively studied in the context of neutron stars over the past few decades. In this work, we investigate the adiabatic radial oscillation stability of neutron stars within the framework of Starobinsky gravity. We find that gravitational modifications can significantly impact stellar stability. Specifically, the higher-derivative nature of the theory causes the exterior spacetime to dynamically respond to fluid oscillations, in contrast to general relativity where Birkhoff's theorem ensures a static exterior. For stellar models with low central densities, the fundamental frequency becomes nearly independent of the central density when the coupling constant is large. For stellar models with high central densities, the transition from stability to instability still approximately occurs near the maximum-mass configuration, similar to the case in general relativity. Our main analysis is conducted in the Jordan frame of the scalar-tensor gravity equivalent to Starobinsky gravity, and we explicitly verify consistency with results obtained in the Einstein frame. We further extend our study to a class of Gauss-Bonnet extensions of Starobinsky gravity.
format Preprint
id arxiv_https___arxiv_org_abs_2507_18916
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Radial oscillations of neutron stars in Starobinsky gravity and its Gauss-Bonnet extension
Li, Ziyi
Yu, Zhong-Xi
Luo, Zhe
Li, Shoulong
Yu, Hongwei
General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
Starobinsky gravity, as one of the simplest and best-behaved higher-curvature gravity theories, has been extensively studied in the context of neutron stars over the past few decades. In this work, we investigate the adiabatic radial oscillation stability of neutron stars within the framework of Starobinsky gravity. We find that gravitational modifications can significantly impact stellar stability. Specifically, the higher-derivative nature of the theory causes the exterior spacetime to dynamically respond to fluid oscillations, in contrast to general relativity where Birkhoff's theorem ensures a static exterior. For stellar models with low central densities, the fundamental frequency becomes nearly independent of the central density when the coupling constant is large. For stellar models with high central densities, the transition from stability to instability still approximately occurs near the maximum-mass configuration, similar to the case in general relativity. Our main analysis is conducted in the Jordan frame of the scalar-tensor gravity equivalent to Starobinsky gravity, and we explicitly verify consistency with results obtained in the Einstein frame. We further extend our study to a class of Gauss-Bonnet extensions of Starobinsky gravity.
title Radial oscillations of neutron stars in Starobinsky gravity and its Gauss-Bonnet extension
topic General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2507.18916