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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 2009-11-07 M. K. Mak , T. Harko

We study the r-modes and rotational ``hybrid'' modes of relativistic stars. As in Newtonian gravity, the spectrum of low-frequency rotational modes is highly sensitive to the stellar equation of state. If the star and its perturbations obey…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Keith H. Lockitch , Nils Andersson , John L. Friedman

When rotation is not taken into account, the measurement of the Gravitational Redshift can provide unique information about the compactness ($M/R$) of the star. Rotation alters the gravitational redshift rendering thereby a unique…

Astrophysics · Physics 2011-06-10 Paul Nunez , Marek Nowakowski

The rotation rate of a star has important implications for the detectability, characterisation and stability of any planets that may be orbiting it. This chapter gives a brief overview of stellar rotation before describing the methods used…

Earth and Planetary Astrophysics · Physics 2018-12-05 P. F. L. Maxted

We study the evolution of magnetized and rigidly rotating neutron stars within a fully general relativistic implementation of ideal magnetohydrodynamics with no assumed symmetries in three spatial dimensions. The stars are modeled as…

General Relativity and Quantum Cosmology · Physics 2010-08-24 Steven L. Liebling , Luis Lehner , David Neilsen , Carlos Palenzuela

We investigate the viscosity driven instability in rotating relativistic stars by means of an iterative approach. We focus on polytropic rotating equilibrium stars and impose an m=2 perturbationin the lapse. We vary both the stiffness of…

Astrophysics · Physics 2007-05-23 Motoyuki Saijo , Eric Gourgoulhon

When a relativistic star rotates slowly and rigidly, centrifugal forces flatten it slightly, thereby catalyzing a small admixture of quadrupolar vibration into its radial modes and a damping of the resulting quasi-radial modes. The damping…

General Relativity and Quantum Cosmology · Physics 2025-09-09 James B. Hartle , Kip S. Thorne

A rotating star may be modeled as a continuous system of particles attracted to each other by gravity and with a given total mass and prescribed angular velocity. Mathematically this leads to the Euler-Poisson system. A white dwarf star is…

Analysis of PDEs · Mathematics 2019-08-07 Walter Strauss , Yilun Wu

We present an asymptotic theory that describes regular frequency spacings of pressure modes in rapidly rotating stars. We use an asymptotic method based on an approximate solution of the pressure wave equation constructed from a stable…

Solar and Stellar Astrophysics · Physics 2012-09-27 Michael Pasek , François Lignières , Bertrand Georgeot , Daniel R. Reese

Using the nuclear equation of states for a large variety of relativistic and non-relativistic force parameters, we calculate the static and rotating masses and radii of neutron stars. From these equation of states, we also evaluate the…

Solar and Stellar Astrophysics · Physics 2013-12-23 Shailesh K. Singh , S. K. Biswal , M. Bhuyan , T. K. Jha , S. K. Patra

A simple classification is given of the anisotropic relativistic star models, resembling the one of charged isotropic solutions. On the ground of this database, and taking into account the conditions for physically realistic star models, a…

General Relativity and Quantum Cosmology · Physics 2018-01-24 B. V. Ivanov

According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole…

General Relativity and Quantum Cosmology · Physics 2016-01-27 Kalin V. Staykov , Daniela D. Doneva , Stoytcho S. Yazadjiev

Using a fully general relativistic implementation of ideal magnetohydrodynamics with no assumed symmetries in three spatial dimensions, the dynamics of magnetized, rigidly rotating neutron stars are studied. Beginning with fully consistent…

General Relativity and Quantum Cosmology · Physics 2010-02-12 Steven L. Liebling

We calculate static and spherically symmetric solutions for the Rastall modification of gravity to describe Neutron Stars (NS). The key feature of the Rastall gravity is the non-conservation of the energy-momentum tensor proportionally to…

General Relativity and Quantum Cosmology · Physics 2016-10-24 A. M. Oliveira , H. E. S. Velten , J. C. Fabris , L. Casarini

The equations describing nonradial adiabatic oscillations of differentially rotating relativistic stars are derived in relativistic slow rotation approximation. The differentially rotating configuration is described by a perturbative…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Adamantios Stavridis , Andrea Passamonti , Kostas Kokkotas

In this chapter we will introduce an effective equation of state (EoS) model based on polytropes that serves to study the so called "mass twins" scenario, where two compact stars have approximately the same mass but (significant for…

High Energy Astrophysical Phenomena · Physics 2020-04-21 David Blaschke , David Edwin Alvarez-Castillo , Alexander Ayriyan , Hovik Grigorian , Noshad Khosravi Lagarni , Fridolin Weber

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 numerically calculate equilibrium configurations of uniformly rotating and charged neutron stars, in the case of insulating material and neglecting the electromagnetic forces acting on the equilibrium of the fluid. This allows us to…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Jerome Novak , Emmanuel Marcq

The present work is to introduce a new kind of modified gravitational theory, named as $f(\mathcal{R,G,T})$ (also $f(\mathcal{R,T,G})$) gravity, where $\mathcal{R}$ is the Ricci scalar, $\mathcal{G}$ is Gauss-Bonnet invariant and…

General Relativity and Quantum Cosmology · Physics 2021-11-16 M. Ilyas

We review the quest of modeling rapidly rotating stars during the past 40 years and detail the challenges to be taken up by models facing new data from interferometry, seismology, spectroscopy... We then present the progress of the ESTER…

Astrophysics · Physics 2007-05-23 M. Rieutord