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In the present paper we examine gravitational wave asteroseismology relations for f-modes of rapidly rotating neutron stars. An approach different to the previous studies is employed - first, the moment of inertia is used instead of the…

Solar and Stellar Astrophysics · Physics 2015-12-09 Daniela D. Doneva , Kostas D. Kokkotas

We study viscosity of the neutron star matter and $r$-mode instability in rotating neutron stars. Contributions to the shear and bulk viscosities from various processes are calculated with account of in-medium modifications of the…

Nuclear Theory · Physics 2015-06-23 E. E. Kolomeitsev , D. N. Voskresensky

We study the magnetic helicity evolution in neutron stars (NSs). First, we analyze how the surface terms affect the conservation law for the sum of the chiral imbalance of the charged particle densities and the density of the magnetic…

High Energy Astrophysical Phenomena · Physics 2024-01-29 Maxim Dvornikov

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

The first results of numerical analysis of classical r-modes of {\it rapidly} rotating compressible stellar models are reported. The full set of linear perturbation equations of rotating stars in Newtonian gravity are numerically solved…

Astrophysics · Physics 2009-10-31 Shin'ichirou Yoshida , Shigeyuki Karino , Shijun Yoshida , Yoshiharu Eriguchi

Rigid (Uniform) rotation is usually assumed when investigating the properties of mature neutron stars (NSs). Although it simplifies their description, it is an assumption because we cannot observe the NS's innermost parts. Here, we analyze…

High Energy Astrophysical Phenomena · Physics 2024-10-18 Jonas P. Pereira , Tulio Ottoni , Jaziel G. Coelho , Jorge A. Rueda , Rafael C. R. de Lima

Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\phi}$ for all values of…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John L. Friedman , Sharon M. Morsink

We examine the influence of quadrupole moment of a slowly rotating neutron star (NS) on the oscillations of a fluid accretion disk (torus) orbiting a compact object the spacetime around which is described by the Hartle-Thorne geometry.…

The forced motion of superfluid vortices in shear oscillations of rotating solid neutron star matter produces damping of the mode. A simple model of the unpinning and repinning processes is described, with numerical calculations of the…

Astrophysics · Physics 2009-11-07 P. B. Jones

When time reversal is broken the viscosity tensor can have a non vanishing odd part. In two dimensions, and only then, such odd viscosity is compatible with isotropy. Elementary and basic features of odd viscosity are examined by…

Fluid Dynamics · Physics 2007-05-23 J. E. Avron

At densities below the neutron drip threshold, a purely elastic solid model (including, if necessary, a frozen-in magnetic field) can provide an adequate description of a neutron star crust, but at higher densities it will be necessary to…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Brandon Carter , Lars Samuelsson

Within the framework of $f(R,T)$ theories of gravity, we investigate the hydrostatic equilibrium of anisotropic neutron stars with a physically relevant equation of state (EoS) for the radial pressure. In particular, we focus on the $f(R,T)…

General Relativity and Quantum Cosmology · Physics 2023-01-10 Juan M. Z. Pretel

We examine the dynamics of a rotating viscous fluid following an abrupt change in the angular velocity of the solid bounding surface. We include the effects of a density stratification and compressibility which are important in…

Astrophysics · Physics 2014-10-13 Mark Abney , Richard I Epstein

We general relativistically calculate the frequency of fundamental torsional oscillations of neutron star crusts, where we focus on the crystalline properties obtained from macroscopic nuclear models in a way depending on the equation of…

High Energy Astrophysical Phenomena · Physics 2012-05-22 Hajime Sotani , Ken'ichiro Nakazato , Kei Iida , Kazuhiro Oyamatsu

We analyze damping of oscillations of general relativistic superfluid neutron stars. To this aim we extend the method of decoupling of superfluid and normal oscillation modes first suggested in [Gusakov & Kantor PRD 83, 081304(R) (2011)].…

Solar and Stellar Astrophysics · Physics 2013-05-21 M. E. Gusakov , E. M. Kantor , A. I. Chugunov , L. Gualtieri

We show that gravitational radiation drives an instability in hot young rapidly rotating neutron stars. This instability occurs primarily in the l=2 r-mode and will carry away most of the angular momentum of a rapidly rotating star by…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Lee Lindblom , Benjamin J. Owen , Sharon M. Morsink

We calculate the disk and boundary layer luminosities for accreting rapidly rotating neutron stars with low magnetic fields in a fully general relativistic manner. Rotation increases the disk luminosity and decreases the boundary layer…

Astrophysics · Physics 2007-05-23 Arun V. Thampan , Bhaskar Datta

Techniques are developed here for evaluating the r-modes of rotating neutron stars through second order in the angular velocity of the star. Second-order corrections to the frequencies and eigenfunctions for these modes are evaluated for…

General Relativity and Quantum Cosmology · Physics 2016-08-25 Lee Lindblom , Gregory Mendell , Benjamin J. Owen

Viscous resistance to changes in the volume of a gas arises when different degrees of freedom have different relaxation times. Collisions tend to oppose the resulting departures from equilibrium and, in so doing, generate entropy. Even for…

Astrophysics · Physics 2008-11-26 X. Chen , E. A. Spiegel

Just as a rotating magnetised neutron star has material pulled away from its surface to populate a magnetosphere, a similar process can occur as a result of neutron-star pulsations rather than rotation. This is of interest in connection…

General Relativity and Quantum Cosmology · Physics 2009-11-13 Ernazar B. Abdikamalov , Bobomurat J. Ahmedov , John C. Miller