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Related papers: Nonradial instabilities in anisotropic neutron sta…

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With (non-barotropic) equations of state valid even when the neutron, proton and electron content of neutron star cores is not in beta equilibrium, we study inertial and composition gravity modes of relativistic rotating neutron stars. We…

General Relativity and Quantum Cosmology · Physics 2009-11-10 L. Villain , S. Bonazzola , P. Haensel

We study the inertial modes of slowly rotating, fully relativistic compact stars. The equations that govern perturbations of both barotropic and non-barotropic models are discussed, but we present numerical results only for the barotropic…

General Relativity and Quantum Cosmology · Physics 2009-11-07 K. H. Lockitch , J. L. Friedman , N. Andersson

We develop a general formalism to treat, in general relativity, the linear oscillations of a two-fluid star about static (non-rotating) configurations. Such a formalism is intended for neutron stars, whose matter content can be described,…

General Relativity and Quantum Cosmology · Physics 2009-10-31 G. L. Comer , David Langlois , Lap Ming Lin

We study the stability of neutron stars with toroidal magnetic fields by magnetohydrodynamic simulation in full general relativity under assumption of axial symmetry. Nonrotating and rigidly rotating neutron stars are prepared for a variety…

Astrophysics · Physics 2008-12-18 Kenta Kiuchi , Masaru Shibata , Shijun Yoshida

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2017-10-04 T. Harko , M. K. Mak

We perform the first study of the oscillation frequencies of rapidly rotating neutron stars in alternative theories of gravity, focusing mainly on the fundamental $f$-modes. We concentrated on a particular class of alternative theories -…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Stoytcho S. Yazadjiev , Daniela D. Doneva , Kostas D. Kokkotas

In this paper, we study the impact of anisotropy on neutron stars with different equations of state, which have been modeled by a piecewise polytropic function with continuous sound speed. Anisotropic pressure in neutron stars is often…

High Energy Astrophysical Phenomena · Physics 2024-01-22 L. M. Becerra , E. A. Becerra-Vergara , F. D. Lora-Clavijo

A new class of solutions describing analytical solutions for compact stellar structures has been developed within the tenets of General Relativity. Considering the inherent anisotropy in compact stars, a stable and causal model for…

General Relativity and Quantum Cosmology · Physics 2021-10-14 Jay Solanki , Bhashin Thakore

We propose a new method to study the quasi-normal modes of rotating relativistic stars. Oscillations are treated as perturbations in the frequency domain of the stationary, axisymmetric background describing a rotating star. The perturbed…

General Relativity and Quantum Cosmology · Physics 2008-11-26 V. Ferrari , L. Gualtieri , S. Marassi

We discuss the dependence of the pulsation frequencies of the axial quasi-normal modes of a nonrotating neutron star upon the equation of state describing the star interior. The continued fraction method has been used to compute the complex…

General Relativity and Quantum Cosmology · Physics 2009-10-31 O. Benhar , E. Berti , V. Ferrari

Non-rotating neutron stars are generally treated in theoretical studies as perfect spheres. Such a treatment, however, may not be correct if strong magnetic fields are present (such as for magnetars) and/or the pressure of the matter in the…

Solar and Stellar Astrophysics · Physics 2015-04-14 O. Zubairi , W. Spinella , A. Romero , R. Mellinger , F. Weber , M. Orsaria , G. Contrera

We investigate the properties of r-mode and inertial mode of slowly rotating, non-isentropic, Newtonian stars, by taking account of the effects of the Coriolis force and the centrifugal force. For the non-isentropic models we consider only…

Astrophysics · Physics 2010-11-19 Shijun Yoshida , Umin Lee

We study non-radial oscillations of neutron stars with superfluid baryons, in a general relativistic framework, including finite temperature effects. Using a perturbative approach, we derive the equations describing stellar oscillations,…

General Relativity and Quantum Cosmology · Physics 2014-07-09 L. Gualtieri , E. M. Kantor , M. E. Gusakov , A. I. Chugunov

Material accreted onto a neutron star can stably burn in steady state only when the accretion rate is high (typically super-Eddington) or if a large flux from the neutron star crust permeates the outer atmosphere. For such situations we…

Astrophysics · Physics 2009-11-10 Anthony L. Piro , Lars Bildsten

We present a new survey of the radial oscillation modes of neutron stars. This study complements and corrects earlier studies of radial oscillations. We present an extensive list of frequencies for the most common equations of state and…

General Relativity and Quantum Cosmology · Physics 2011-05-23 Kostas. D. Kokkotas , Johannes Ruoff

In this work, we have made a systematic study of how the gravitational wave frequency of the fundamental mode from compact stars is affected by anisotropic effects using realistic equations of state. Our study is an extension of the seminal…

General Relativity and Quantum Cosmology · Physics 2024-03-19 Elvis J. Aquino Curi , Luis B. Castro , Cesar V. Flores , César H. Lenzi

The effects of nonlinear oscillations in compact stars are attracting considerable current interest. In order to study such phenomena in the framework of fully nonlinear general relativity, highly accurate numerical studies are required. We…

General Relativity and Quantum Cosmology · Physics 2009-09-24 Michael Gabler , Ulrich Sperhake , Nils Andersson

Rapidly rotating neutron stars can be unstable to the gravitational-wave-driven CFS mechanism if they have a neutral point in the spectrum of nonaxisymmetric f-modes. We investigate the frequencies of these modes in two sequences of…

Solar and Stellar Astrophysics · Physics 2010-11-16 Burkhard Zink , Oleg Korobkin , Erik Schnetter , Nikolaos Stergioulas

Neutron stars provide an excellent laboratory for physics under the most extreme conditions. Up to now, models of axisymmetric, stationary, differentially rotating neutron stars were constructed under the strong assumption of barotropicity,…

General Relativity and Quantum Cosmology · Physics 2019-12-11 Giovanni Camelio , Tim Dietrich , Miguel Marques , Stephan Rosswog

We study axial quasinormal modes of static neutron stars in the nonminimal derivative coupling sector of Horndeski theory. We focus on the fundamental curvature mode, which we analyse for ten different equations of state with different…

General Relativity and Quantum Cosmology · Physics 2018-05-09 Jose Luis Blázquez-Salcedo , Kevin Eickhoff