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For four newly suggested microscopic equations of state of neutron star matter, we construct equilibrium sequences of rapidly rotating neutron stars in general relativity. The sequences are the normal and supramassive evolutionary sequences…

Astrophysics · Physics 2016-08-15 B. Datta , A. V. Thampan , I. Bombaci

We investigate the dynamical stability of bootstrapped Newtonian stars following homologous adiabatic perturbations, focusing on objects of low or intermediate compactness. The results show that for stars with homogeneous densities these…

General Relativity and Quantum Cosmology · Physics 2024-08-08 Octavian Micu

We use a modified Einstein-Maxwell gravity to study stability of an electrostatic spherical star. Correction terms in this model are scalers which are made from contraction of Ricci tensor and electromagnetic vector potential. Our…

General Relativity and Quantum Cosmology · Physics 2023-12-05 Hossein Ghaffarnejad , Tohid Ghorbani , Firoozeh Eidizadeh

We formulate the equations of equilibrium of neutron stars taking into account strong, weak, electromagnetic, and gravitational interactions within the framework of general relativity. The nuclear interactions are described by the exchange…

Solar and Stellar Astrophysics · Physics 2012-06-01 Riccardo Belvedere , Daniela Pugliese , Jorge A. Rueda , Remo Ruffini , She-Sheng Xue

We analyze several aspects of the recently noted neutron star collapse instability in close binary systems. We utilize (3+1) dimensional and spherical numerical general relativistic hydrodynamics to study the origin, evolution, and…

Astrophysics · Physics 2009-10-30 G. J. Mathews , J. R. Wilson

We provide a summary of several parametrisations for the nuclear equation of state that have been proposed over the past decades and list viable ranges for their parameters. Based on these parametrisations, we construct a large database of…

General Relativity and Quantum Cosmology · Physics 2025-11-27 Christian J. Krüger , Mariachiara Celato

We present our study of stability of differentially rotating, axisymmetric neutron stars described by a polytropic equation of state with $\Gamma = 2$. We focus on quasi-toroidal solutions with a degree of differential rotation $\widetilde…

High Energy Astrophysical Phenomena · Physics 2024-02-29 Paweł Szewczyk , Dorota Gondek-Rosińska , Pablo Cerdá-Durán

Regarding a $d-$dimensional spherically symmetric line element in the context of Einstein-$\Lambda$ gravity, the hydrostatic equilibrium equation of stars is obtained. Then, by using the lowest order constrained variational (LOCV) method…

General Relativity and Quantum Cosmology · Physics 2017-01-30 G. H. Bordbar , S. H. Hendi , B. Eslam Panah

After giving an overview of the history and idea of neutron stars, I shall introduce, in part one of my lectures, a representative collection of models for the equation of state of superdense neutron star matter, which account for various…

Astrophysics · Physics 2007-05-23 Fridolin Weber , Norman K. Glendenning

We prove general nonlinear stability and existence theorems for rotating star solutions which are axi-symmetric steady-state solutions of the compressible isentropic Euler-Poisson equations in 3 spatial dimensions. We apply our results to…

General Relativity and Quantum Cosmology · Physics 2014-08-04 Tao Luo , Joel Smoller

In this chapter we review the recent results on the equilibrium configurations of static and uniformly rotating neutron stars within the Hartle formalism. We start from the Einstein-Maxwell-Thomas-Fermi equations formulated and extended by…

High Energy Astrophysical Phenomena · Physics 2016-09-03 Kuantay Boshkayev

We investigate the dynamic stability of inspiraling neutron stars by performing multiple-orbit numerical relativity simulations of the binary neutron star inspiral process. By introducing eccentricities in the orbits of the neutron stars,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Mark Miller

The conformal flatness approximation to the Einstein equations has been successfully used in many astrophysical applications such as initial data constructions and dynamical simulations. Although it has been shown that full general…

This paper is devoted to study the stability/instability of the expansionfree self gravitating source in the framework of Einstein Gauss-Bonnet gravity. The source has been taken as Tolman-Bondi model which is homogenous in nature. The…

General Relativity and Quantum Cosmology · Physics 2015-04-22 G. Abbas , S. Sarwar

The present work investigates the numerical evolution of linearized oscillations of non-rotating, spherically symmetric neutron stars within the framework of general relativity. We derive the appropriate equations using the (3+1)-formalism.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Johannes Ruoff

We investigate the evolution of rigidly and differentially rotating protoneutron stars (PNSs) during the first twenty seconds of their life. We solve the equations describing stationary axisymmetric configurations in general relativity…

Astrophysics · Physics 2007-05-23 Loic Villain , Jose A. Pons , Pablo Cerda-Duran , Eric Gourgoulhon

General-relativistic equilibria of differentially rotating stars are expected in a number of astrophysical scenarios, from core-collapse supernovae to the remnant of binary neutron-star mergers. The latter, in particular, have been the…

General Relativity and Quantum Cosmology · Physics 2024-06-18 Marie Cassing , Luciano Rezzolla

Modelling isolated rotating stars at any rotation rate is a challenge for the next generation of stellar models. These models will couple dynamical aspects of rotating stars, like angular momentum and chemicals transport, with classical…

Solar and Stellar Astrophysics · Physics 2015-06-11 Michel Rieutord , Francisco Espinosa Lara

We investigate the geodesic structure of realistic static and spherically symmetric spacetimes embedding neutron stars in metric $f(R)$ gravity, focusing on the quadratic Starobinsky model $f(R)=aR^2$ with $a<0$. Neutron-star solutions are…

General Relativity and Quantum Cosmology · Physics 2026-03-10 Néstor Rivero González , Álvaro de la Cruz Dombriz , Gonzalo J. Olmo

Most of the properties of black holes can be mimicked by horizonless compact objects such as gravastars and boson stars. We show that these ultra-compact objects develop a strong ergoregion instability when rapidly spinning. Instability…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Vitor Cardoso , Paolo Pani , Mariano Cadoni , Marco Cavaglia