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Related papers: Anisotropic neutron stars in $R^2$ gravity

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We investigate the effects of relativity on the gravitational instability of finite isothermal gaseous spheres. In the first part of the paper, we treat the gravitational field within the framework of Newtonian mechanics but we use a…

Astrophysics · Physics 2009-11-07 Pierre-Henri Chavanis

We investigate the spacetime of anisotropic stars admitting conformal motion. The Einstein field equations are solved using different ansatz of the surface tension. In this investigation, we study two cases in details with the anisotropy…

Astrophysics · Physics 2009-12-15 Farook Rahaman , Mubasher Jamil , Mehedi Kalam , Kaushik Chakraborty , Ashis Ghosh

Many physically inspired general relativity (GR) modifications predict significant deviations in the properties of spacetime surrounding massive neutron stars. Among these modifications is $f(\mathcal{R}, \mathbb{T})$, where $\mathcal{R}$…

General Relativity and Quantum Cosmology · Physics 2023-08-21 G. G. L Nashed

In this work we investigate neutron stars (NS) in $f(\mathcal{R,T})$ gravity for the case $R+2\lambda\mathcal{T}$, $\mathcal{R}$ is the Ricci scalar and $\mathcal{T}$ the trace of the energy-momentum tensor. The hydrostatic equilibrium…

High Energy Astrophysical Phenomena · Physics 2021-01-01 R. Lobato , O. Lourenço , P. H. R. S. Moraes , C. H. Lenzi , M. de Avellar , W. de Paula , M. Dutra , M. Malheiro

Using time evolutions of the relevant linearised equations we study non-axisymmetric oscillations of rapidly rotating and superfluid neutron stars. We consider perturbations of Newtonian axisymmetric background configurations and account…

Astrophysics · Physics 2009-11-13 Andrea Passamonti , Brynmor Haskell , Nils Andersson

We develop a fully relativistic framework to study the rotational response of gravitationally coupled two-fluid neutron stars within the slow-rotation approximation. Treating the two components as independently conserved perfect fluids…

High Energy Astrophysical Phenomena · Physics 2026-03-16 Ankit Kumar , Hajime Sotani

We study the structure of neutron stars in f(R) gravity theories with perturbative constraints. We derive the modified Tolman-Oppenheimer-Volkov equations and solve them for a polytropic equation of state. We investigate the resulting…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Alan Cooney , Simon DeDeo , Dimitrios Psaltis

We have developed a theoretical model and a numerical code for stationary rotating superfluid neutron stars in full general relativity. The underlying two-fluid model is based on Carter's covariant multi-fluid hydrodynamic formalism. The…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Reinhard Prix , Jerome Novak , G. L. Comer

It is shown how to set up a mathematically elegant and fully relativistic superfluid model that can provide a realistic approximation (neglecting small anisotropies due to crust solidity, magnetic fields, et cetera, but allowing for the…

Astrophysics · Physics 2009-10-30 David Langlois , David M. Sedrakian , Brandon Carter

In this lecture, we give a first introduction to neutron stars, based on fundamental physical principles. After outlining their amazing macroscopic properties, as obtained from observations, we infer the extreme conditions of matter in…

High Energy Astrophysical Phenomena · Physics 2010-01-11 Pierre M. Pizzochero

A number of properties of dense matter can be understood semiquantitatively in terms of simple physical arguments. We begin with the outer parts of neutron stars, and consider the density at which pressure ionization occurs, the density at…

Nuclear Theory · Physics 2020-03-18 C. J. Pethick

We consider static spherically symmetric self-gravitating configurations of the perfect fluid within the framework of the torsion-based extended theory of gravity. In particular, we use the covariant formulation of $f(T)$ gravity with $f(T)…

General Relativity and Quantum Cosmology · Physics 2018-10-03 Sasa Ilijic , Marko Sossich

We study Einstein static universes in the context of generic f(R) models. It is shown that Einstein static solutions exist for a wide variety of modified gravity models sourced by a barotropic perfect fluid with equation of state w=p/rho,…

General Relativity and Quantum Cosmology · Physics 2009-03-14 Sanjeev S. Seahra , Christian G. Boehmer

Probing gravity in its strongest regime is a central goal of modern physics, as the nature of the most compact objects reflects fundamental aspects of Einstein's theory of general relativity (GR). In GR, black holes are regarded as the most…

General Relativity and Quantum Cosmology · Physics 2026-05-20 Shoulong Li , H. Lü , Yong Gao , Rui Xu , Lijing Shao , Hongwei Yu

The relativistic fluid is a highly successful model used to describe the dynamics of many-particle systems moving at high velocities and/or in strong gravity. It takes as input physics from microscopic scales and yields as output…

General Relativity and Quantum Cosmology · Physics 2021-07-07 N. Andersson , G. L. C. Comer

We build slowly rotating anisotropic neutron stars using the Hartle-Thorne formalism, employing three distinct anisotropy models--Horvat, Bowers-Liang, and a covariant model--to characterize the relationship between radial and tangential…

High Energy Astrophysical Phenomena · Physics 2025-04-24 L. M. Becerra , E. A. Becerra-Vergara , F. D. Lora-Clavijo

In this paper, we consider a spherical symmetric metric to extract the hydrostatic equilibrium equation of stars in $(3+1)-$dimensional gravity's rainbow in the presence of cosmological constant. Then, we generalize the hydrostatic…

High Energy Physics - Theory · Physics 2016-09-19 S. H. Hendi , G. H. Bordbar , B. Eslam Panah , S. Panahiyan

As mature neutron stars are cold (on the relevant temperature scale), one has to carefully consider the state of matter in their interior. The outer kilometer or so is expected to freeze to form an elastic crust of increasingly neutron-rich…

High Energy Astrophysical Phenomena · Physics 2021-03-19 N. Andersson

Modified gravity is one of the potential candidates to explain the accelerated expansion of the universe. Current study highlights the materialization of anisotropic compact stars in the context of $f(R,G)$ theory of gravity. In particular,…

General Physics · Physics 2017-07-07 M. Farasat Shamir , Saeeda Zia

Recent calculations indicate that in the outer parts of neutron stars nuclei are rod-like or slab-like, rather than roughly spherical. We consider the elastic properties of these phases, and argue that they behave as liquid crystals, rather…

Astrophysics · Physics 2009-10-30 C. J. Pethick , A. Y. Potekhin
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