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Related papers: Bulk viscosity in hyperonic star and r-mode instab…

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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

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

As an extension of our previous work, we investigate the dynamical instability against nonaxisymmetric bar-mode deformations of differentially rotating stars in Newtonian gravity varying the equations of state and velocity profiles. We…

Astrophysics · Physics 2009-11-07 Masaru Shibata , Shigeyuki Karino , Yoshiharu Eriguchi

We determine characteristic timescales for the viscous damping of r-mode oscillations in rapidly rotating compact stars that contain quark matter. We present results for the color-flavor-locked (CFL) phase of dense quark matter, in which…

Nuclear Theory · Physics 2010-04-15 Prashanth Jaikumar , Gautam Rupak , Andrew W. Steiner

Rossby waves (r-modes) have been suggested as a means to regulate the spin periods of young or accreting neutron stars, and also to produce observable gravitational wave radiation. R-modes involve primarily transverse, incompressive motions…

Astrophysics · Physics 2009-10-31 Yanqin Wu , Christopher D. Matzner , Phil Arras

Studying the frequency and temperature evolution of a compact star can give us valuable information about the microscopic properties of the matter inside the star. In this paper we study the effect of dissipative reheating of a neutron star…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Mark G. Alford , Simin Mahmoodifar , Kai Schwenzer

We explore the dynamics of the r-modes in accreting neutron stars in two ways. First, we explore how dissipation in the magneto-viscous boundary layer (MVBL) at the crust-core interface governs the damping of r-mode perturbations in the…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Justin B. Kinney , Gregory Mendell

Rotating neutron stars (NSs) are crucial objects of study, as our understanding of them relies significantly on observational data from these rotating stars. Observations suggest that the magnetic fields of NSs range from approximately…

General Relativity and Quantum Cosmology · Physics 2025-09-09 Muhammad Lawrence Pattersons , Freddy Permana Zen

We study bulk viscosity arising from weak current Urca processes in dense baryonic matter at and beyond nuclear saturation density. We consider the temperature regime where neutrinos are trapped and therefore have nonzero chemical…

High Energy Astrophysical Phenomena · Physics 2019-11-27 Mark Alford , Arus Harutyunyan , Armen Sedrakian

We discuss the basic hydrodynamics that determines the density structure of the disks around hot stars. Observational evidence supports the idea that these disks are Keplerian (rotationally supported) gaseous disks. A popular scenario in…

Astrophysics · Physics 2009-11-13 A. C. Carciofi , J. E. Bjorkman

We study the properties of rotating neutron stars within a generalized chiral SU(3)-flavor model. The influence of the rotation on the inner structure and the hyperon matter content of the star is discussed. We calculate the Kepler…

Nuclear Theory · Physics 2008-11-26 S. Schramm , D. Zschiesche

A phase transition occurring in the inner core of a neutron star could be associated to a density discontinuity that would affect the frequency spectrum of the non-radial oscillation modes in two ways. Firstly, it would produce a softening…

Astrophysics · Physics 2009-11-07 G. Miniutti , J. A. Pons , E. Berti , L. Gualtieri , V. Ferrari

We demonstrate that there exists a new mechanism for dissipating the energy of stellar oscillations. For neutron stars, in particular, we show that the mechanical energy of density perturbations is not only dissipated to heat via bulk…

Solar and Stellar Astrophysics · Physics 2010-06-24 Basil A. Sa'd , Jürgen Schaffner-Bielich

We investigate the oscillations of slowly rotating superfluid stars, taking into account the vortex mediated mutual friction force that is expected to be the main damping mechanism in mature neutron star cores. Working to linear order in…

Astrophysics · Physics 2009-07-30 N. Andersson , K. Glampedakis , B. Haskell

Accreting neutron stars (NS) can exhibit high frequency modulations in their lightcurves during thermonuclear X-ray bursts, known as burst oscillations. These frequencies can be offset from the NS spin frequency by several Hz (where known…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Frank R. N. Chambers , Anna L. Watts

In this work, we investigate hot, isentropic compact stars in the limiting cases of static and maximally rotating configurations, focusing on how variations in the symmetry energy of the equation of state derived from covariant density…

High Energy Astrophysical Phenomena · Physics 2026-02-02 Stefanos Tsiopelas , Armen Sedrakian , Micaela Oertel

We investigate the dynamics of r modes at amplitudes in the nonlinear regime for rapidly but uniformly rotating neutron stars with a polytropic equation of state. For this, we perform three-dimensional relativistic hydrodynamical…

General Relativity and Quantum Cosmology · Physics 2013-05-29 Wolfgang Kastaun

The oscillation modes of stars play an important role in observations, and on the understanding of stellar stability properties. The role of viscosity in the oscillation modes of compact stars has been so far understood very loosely only,…

General Relativity and Quantum Cosmology · Physics 2026-04-16 Sofía Bussières , Jaime Redondo-Yuste , José Javier Ortega Gómez , Vitor Cardoso

The identification of non-radial g-mode oscillations as the cause of variability in cool subdwarf B stars (PG1716 variables) has been frustrated by a 5 000 K discrepancy between the observed and theoretical blue edge of the instability…

Astrophysics · Physics 2009-11-11 C. S. Jeffery , H. Saio

Nonlinear evolution of the gravitational radiation (GR) driven instability in the r-modes of neutron stars is studied by full numerical 3D hydrodynamical simulations. The growth of the r-mode instability is found to be limited by the…

Astrophysics · Physics 2009-11-07 Lee Lindblom , Joel E. Tohline , Michele Vallisneri