Nonaxisymmetric Neutral Modes in Rotating Relativistic Stars

Abstract

We study nonaxisymmetric perturbations of rotating relativistic stars. modeled as perfect-fluid equilibria. Instability to a mode with angular dependence $\exp (im\varphi )$ sets in when the frequency of the mode vanishes. The locations of these zero-frequency modes along sequences of rotating stars are computed in the framework of general relativity. We consider models of uniformly rotating stars with polytropic equations of state, finding that the relativistic models are unstable to nonaxisymmetric modes at significantly smaller values of rotation than in the Newtonian limit. Most strikingly, the m=2 bar mode can become unstable even for soft polytropes of index $N\le 1.3$, while in Newtonian theory it becomes unstable only for stiff polytropes of index $N\le 0.808$. If rapidly rotating neutron stars are formed by the accretion-induced collapse of white dwarfs, instability associated with these nonaxisymmetric, gravitational-wave driven modes may set an upper limit on neutron-star rotation. Consideration is restricted to perturbations that correspond to polar perturbations of a spherical star. A study of axial perturbations is in progress.

57 pages, 9 figures

References in corpus (1)

• Construction of Highly Accurate Models of Rotating Neutron Stars - Comparison of Three Different Numerical Schemes

Cited by in corpus (74)

• Physics, Astrophysics and Cosmology with Gravitational Waves
• A new class of unstable modes of rotating relativistic stars
• Rotating Stars in Relativity
• Axial instability of rotating relativistic stars
• The r-mode instability in rotating neutron stars
• On the Maximum Mass of Differentially Rotating Neutron Stars
• Gravitational radiation limit on the spin of young neutron stars
• Gravitational waves from instabilities in relativistic stars
• On the relevance of the r-mode instability for accreting neutron stars and white dwarfs
• Gravitational wave astronomy
• Numerical Relativity: A review
• Rotating Stars in Relativity
• Gravitational waves from neutron stars: Promises and challenges
• Towards Understanding Astrophysical Effects of Nuclear Symmetry Energy
• Gravitational wave asteroseismology of fast rotating neutron stars with realistic equations of state
• The bar-mode instability in differentially rotating neutron stars: Simulations in full general relativity
• Fully general relativistic simulation of coalescing binary neutron stars: Preparatory tests
• Dynamical Rotational Instability at Low $T/W$
• General relativistic hydrodynamics with viscosity: contraction, catastrophic collapse, and disk formation in hypermassive neutron stars
• Nonlinear Pulsations in Differentially Rotating Neutron Stars: Mass-Shedding-Induced Damping and Splitting of the Fundamental Mode
• Non-linear axisymmetric pulsations of rotating relativistic stars in the conformal flatness approximation
• The physics of dense hadronic matter and compact stars
• Coalescing Binary Neutron Stars
• Gravitational wave asteroseismology with fast rotating neutron stars
• The rotational modes of relativistic stars: Numerical results
• Oscillations of rapidly rotating relativistic stars
• Stability and collapse of rapidly rotating, supramassive neutron stars: 3D simulations in general relativity
• Approximate Matching of Analytic and Numerical Solutions for Rapidly Rotating Neutron Stars
• Differentially-rotating neutron star models with a parametrized rotation profile
• Secular Instability of g-Modes in Rotating Neutron Stars
• GW190814: On the properties of the secondary component of the binary
• Fast Rotating Relativistic Stars: Spectra and Stability without Approximation
• Dynamical Bar Instability in Rotating Stars: Effect of General Relativity
• Rotating Stars in Relativity
• Equation of state of dense matter and the minimum mass of cold neutron stars
• A Numerical Study of Normal Modes of Rotating Neutron Star Models by the Cowling Approximation
• Axisymmetric collapse simulations of rotating massive stellar cores in full general relativity: Numerical study for prompt black hole formation
• The f-mode instability in relativistic neutron stars
• Quasi-normal modes of rotating relativistic stars - neutral modes for realistic equations of state
• On the frequency band of the f-mode CFS instability
• Models of Rapidly Rotating Neutron Stars: Remnants of Accretion Induced Collapse
• Frequencies of f-modes in differentially rotating relativistic stars and secular stability limits
• Quasi-radial modes of rotating stars in general relativity
• Nonlinear Development of the Secular Bar-mode Instability in Rotating Neutron Stars
• Radiation of Angular Momentum by Neutrinos from Merged Binary Neutron Stars
• The evolution of the f-mode instability in neutron stars and gravitational wave detectability
• Dynamical instability of new-born neutron stars as sources of gravitational radiation
• Constraining properties of rapidly rotating neutron stars using data from heavy-ion collisions
• On the saturation amplitude of the f-mode instability
• Dynamics of Fast Rotating Neutron Stars: An Approach in the Hilbert Gauge
• R-mode oscillations of rapidly rotating barotropic stars in general relativity: Analysis by the relativistic Cowling approximation
• Numerical evolution of secular bar-mode instability induced by the gravitational radiation reaction in rapidly rotating neutron stars
• Bar mode instability in relativistic rotating stars: a post Newtonian treatment
• A new approach to the study of quasi-normal modes of rotating stars
• Constructing a Mass-Current Radiation-Reaction Force For Numerical Simulations
• Jacobi-like bar mode instability of relativistic rotating bodies
• Asteroseismology of rapidly rotating neutron stars - an alternative approach
• Quasi-equilibrium models for triaxially deformed rotating compact stars
• Universal and approximate relations for the gravitational-wave damping timescale of $f$-modes in neutron stars
• Fast Rotating Neutron Stars: Oscillations and Instabilities
• Magnetic Braking in Differentially Rotating, Relativistic Stars
• Gravitational waves from a spinning particle scattered by a relativistic star: Axial mode case
• Gravitational Wave Astronomy
• Gravitational-wave astronomy: the high-frequency window
• Skyrmion Stars: Astrophysical motivations and implications
• A characteristic approach to the quasi-normal mode problem
• Rotating Skyrmion Stars
• Non-axisymmetric oscillations of rapidly rotating relativistic stars by conformal flatness approximation
• Post-Newtonian treatment of bar mode instability in rigidly rotating equilibrium configurations for polytropic stars
• R-mode oscillations of rapidly rotating Newtonian stars - A new numerical scheme and its application to the spin evolution of neutron stars
• Gravitational wave content and stability of uniformly, rotating, triaxial neutron stars in general relativity
• High frequency sources of gravitational waves
• High-density Skyrmion matter and Neutron Stars
• General Relativistic Stability and Gravitational Wave Content of Rotating Triaxial Neutron Stars