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Related papers: Differential rotation and r-modes in magnetized ne…

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We study the cooling evolution of neutron stars with strong poloidal magnetic fields (with strength not far from observed values) using the full general relativity 2-dimensional \textit{Astreus} code, which solves consistently Einstein's…

High Energy Astrophysical Phenomena · Physics 2025-06-12 Rodrigo Negreiros , Jeffrey Peterson , Veronica Dexheimer

We calculate the second order perturbations driven by oscillation modes of rotating stars. Assuming that the typical amplitude $a$ of oscillation modes is small, we expand the perturbed quantities as $Q=Q^{(0)}+Q^{(1)}+Q^{(2)}+\cdots$ where…

Solar and Stellar Astrophysics · Physics 2025-07-11 Umin Lee

Rossby waves (r-modes) in rapidly rotating neutron stars are unstable because of the emission of gravitational radiation. We study saturation of this instability by nonlinear transfer of energy to stellar "inertial" oscillation modes. We…

We study the dynamical evolution of the gravitational-wave driven instability of the f-mode in rapidly rotating relativistic stars. With an approach based on linear perturbation theory we describe the evolution of the mode amplitude and…

Solar and Stellar Astrophysics · Physics 2015-06-11 A. Passamonti , E. Gaertig , K. D. Kokkotas. D. Doneva

The problem of the stability of magnetic fields in stars has a long history and has been investigated in detail in perturbation theory. Here we consider the nonlinear evolution of a non-rotating neutron star with a purely poloidal magnetic…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Riccardo Ciolfi , Samuel K. Lander , Gian Mario Manca , Luciano Rezzolla

We present some results about a novel damping mechanism of r-mode oscillations in neutron stars due to processes that change the number of protons, neutrons and electrons. Deviations from equilibrium of the number densities of the various…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Massimo Mannarelli , Giuseppe Colucci , Cristina Manuel

Instabilities in magnetic fields wound up by differential rotation as reviewed in Spruit (1999) are discussed with some detail and new developments added. In stellar models which include magnetic torques, the differential rotation tends to…

Astrophysics · Physics 2007-05-23 H. C. Spruit

Almost none of the r-modes ordinarily found in rotating stars exist, if the star and its perturbations obey the same one-parameter equation of state; and rotating relativistic stars with one-parameter equations of state have no pure r-modes…

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

We test models for the evolution of neutron star (NS) magnetic fields (B). Our model for the evolution of the NS spin is taken from an analysis of pulsar timing noise presented by Hobbs et al. (2010). We first test the standard model of a…

High Energy Astrophysical Phenomena · Physics 2013-12-12 Shuang-Nan Zhang , Yi Xie

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

In [Gusakov et al.\ PRD, 96, 103012, (2017)], we proposed a self-consistent method to study the quasistationary evolution of the magnetic field in neutron-star cores. Here we apply it to calculate the instantaneous particle velocities and…

High Energy Astrophysical Phenomena · Physics 2018-08-13 D. D. Ofengeim , M. E. Gusakov

Increasing evidence is becoming available about not only the surface differential rotation of rapidly rotating cool stars but, in a small number of cases, also about temporal variations, which possibly are analogous to the solar torsional…

Astrophysics · Physics 2009-11-10 E. Covas , D. Moss , R. Tavakol

Stars are, generically, rotating and magnetised objects with a misalignment between their magnetic and rotation axes. Since a magnetic field induces a permanent distortion to its host, it provides effective rigidity even to a fluid star,…

Solar and Stellar Astrophysics · Physics 2017-03-23 S. K. Lander , D. I. Jones

We study the linear, but fully non-adiabatic tidal response of a uniformly rotating, somewhat evolved X_c=0.4, 10 Msun main sequence star to the dominant l=2 components of its binary companion's tidal potential. This is done numerically…

Astrophysics · Physics 2007-05-23 M. G. Witte , G. J. Savonije

I study the effect of nuclear equation of state on the r-mode instability of a rotating neutron star. I consider the case where the crust of the neutron star is perfectly rigid and I employ the related theory introduced by Lindblom {\it et…

Nuclear Theory · Physics 2015-03-18 Ch. C. Moustakidis

We have studied whether the rotation and magnetic fields in neutrino-driven winds can be key processes for the rapid-process (r-process) nucleosynthesis. We have examined the features of a steady and subsonic wind solutions which extend the…

Astrophysics · Physics 2015-06-24 S. Nagataki , K. Kohri

We consider both mode calculations and time evolutions of axial r-modes for relativistic uniformly rotating non-barotropic neutron stars, using the slow-rotation formalism, in which rotational corrections are considered up to linear order…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Johannes Ruoff , Kostas D. Kokkotas

Based on the accretion induced magnetic a field decay model, in which a frozen field and an incompressible fluid are assumed, we obtain the following results. (1) An analytic relation between the magnetic field and spin period, if the…

Astrophysics · Physics 2007-05-23 K. S. Cheng , C. M. Zhang

We study $m=1$ oscillations and instabilities of magnetised neutron stars, by numerical time-evolution of linear perturbations of the system. The background stars are stationary equilibrium configurations with purely toroidal magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. K. Lander , D. I. Jones

In this paper we review the basics of magneto-rotational properties of neutron stars focusing on spin-up/spin-down behavior at different evolutionary stages. The main goal is to provide equations for the spin frequency changes in various…

High Energy Astrophysical Phenomena · Physics 2024-02-08 P. Abolmasov , A. V. Biryukov , S. B. Popov