Instability windows of relativistic r-modes

Abstract

The detectability of the gravitational-wave signal from $r$-modes depends on the interplay between the amplification of the mode by the CFS instability and its damping due to dissipative mechanisms present in the stellar matter. The instability window of $r$-modes describes the region of stellar parameters (angular velocity, $\Omega$, and redshifted stellar temperature, $T^{\infty }$), for which the mode is unstable. In this study, we reexamine this problem in nonbarotropic neutron stars, taking into account the previously overlooked nonanalytic behavior (in $\Omega$) of relativistic $r$-modes and enhanced energy dissipation resulting from diffusion in superconducting stellar matter. We demonstrate that at slow rotation rates, relativistic $r$-modes exhibit weaker amplification by the CFS instability compared to Newtonian ones. However, their dissipation through viscosity and diffusion is significantly more efficient. In rapidly rotating neutron stars within the framework of general relativity, the amplification of $r$-modes by the CFS mechanism and their damping due to shear viscosity become comparable to those predicted by Newtonian theory. In contrast, the relativistic damping of the mode by diffusion and bulk viscosity remains significantly stronger than in the nonrelativistic case. Consequently, account for diffusion and general relativity leads to a substantial modification of the $r$-mode instability window compared to the Newtonian prediction. This finding is important for the interpretation of observations of rotating neutron stars, as well as for overall understanding of $r$-mode physics.

arXiv comment21 pages, 8 figures, accepted for publication in Physical Review D

References in corpus (47)

• A new class of unstable modes of rotating relativistic stars
• Gravitational waves from hot young rapidly rotating neutron stars
• Gravitational Radiation Instability in Hot Young Neutron Stars
• Axial instability of rotating relativistic stars
• The r-mode instability in rotating neutron stars
• Superfluidity in nuclear systems and neutron stars
• Runaway Heating By R-modes of Neutron Stars in Low Mass X-ray Binaries
• Viscous Boundary Layer Damping of R-Modes in Neutron Stars
• Crust-core coupling and r-mode damping in neutron stars: a toy model
• Tests of the nuclear equation of state and superfluid and superconducting gaps using the Cassiopeia A neutron star
• R-Mode Oscillations and Spindown of Young Rotating Magnetic Neutron Stars
• Accuracy of the relativistic Cowling approximation in slowly rotating stars
• Bulk viscosity in superfluid neutron star cores. II. Modified Urca processes in $npe\mu$ matter
• r-modes and mutual friction in rapidly rotating superfluid neutron stars
• R-modes of accreting hyperon stars as persistent sources of gravitational waves
• R-modes in neutron stars: Theory and observations
• Explaining observations of rapidly rotating neutron stars in LMXBs
• Crust-core coupling in rotating neutron stars
• Rotational modes of non-isentropic stars and the gravitational radiation driven instability
• Chandra studies of the globular cluster 47 Tucanae: A deeper X-ray source catalogue, five new X-ray counterparts to millisecond radio pulsars, and new constraints to r-mode instability window
• How to search for gravitational waves from $r$-modes of known pulsars
• The r-modes in accreting neutron stars with magneto-viscous boundary layers
• Bulk viscosity in neutron stars with hyperon cores
• Temperature effects in pulsating superfluid neutron stars
• R-modes and neutron star recycling scenario
• First searches for gravitational waves from r-modes of the Crab pulsar
• Dissipation in relativistic superfluid neutron stars
• Dissipative relativistic magnetohydrodynamics of a multicomponent mixture and its application to neutron stars
• Bulk viscosity in a neutron star mantle
• Constraining neutron superfluidity with $r$-mode physics
• Relativistic formulation of the Hall-Vinen-Bekarevich-Khalatnikov superfluid hydrodynamics
• Rotochemical Heating of Neutron Stars: Rigorous Formalism with Electrostatic Potential Perturbations
• R-mode frequencies of rapidly and differentially rotating relativistic neutron stars
• Transport coefficients of leptons in superconducting neutron star cores
• Strengthening the bounds on the r-mode amplitude with X-ray observations of millisecond pulsars
• The effect of magnetic fields on the r-modes of slowly rotating relativistic neutron stars
• XMM-Newton detection and spectrum of the second fastest spinning pulsar PSR J0952-0607
• The r-modes of slowly rotating, stratified neutron stars
• Proton pairing in neutron stars from chiral effective field theory
• Diffusion as a leading dissipative mechanism in superconducting neutron stars
• Proton-proton 1S0 pairing in neutron star
• Formulating the r-mode problem for slowly rotating neutron stars
• Resonance suppression of the r-mode instability in superfluid neutron stars: Accounting for muons and entrainment
• Non-analytic behavior of the relativistic r-modes in slowly rotating neutron stars
• Diffusion in superfluid Fermi mixtures: General formalism
• Bulk viscosity in superfluid neutron star cores. I. Direct Urca processes in npeμmatter
• R-mode instability in compact stars

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