Related papers: Constraining neutron superfluidity with $r$-mode p…
We present a simple spin evolution model that predicts that rapidly rotating accreting neutron stars will mainly be confined to a narrow range of spin-frequencies; P= 1.5-5 ms. This is in agreement with current observations of both neutron…
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…
I summarize some constraints on the physics of neutron stars arising from X-ray observations of the surfaces of neutron stars, focusing on using models of low-magnetic-field neutron star atmospheres to interpret their X-ray spectra. I…
We consider an instability of rapidly rotating neutron stars in low-mass X-ray binaries (LMXBs) with respect to excitation of r-modes (which are analogous to Earth's Rossby waves controlled by the Coriolis force). We argue that finite…
We study the dynamical evolution of a large amplitude r-mode by numerical simulations. R-modes in neutron stars are unstable growing modes, driven by gravitational radiation reaction. In these simulations, r-modes of amplitude unity or…
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…
The $r$-modes of accreting neutron stars could be a detectable source of persistent gravitational waves if the bulk viscosity of the stellar matter can prevent a thermal runaway. This is possible if exotic particles such as hyperons are…
Neutron stars accreting matter from low-mass binary companions are observed to undergo bursts of X-rays due to the thermonuclear explosion of material on the neutron star surface. We use recent results on superfluid and superconducting…
Neutron stars that are cold enough should have two or more superfluids/supercondutors in their inner crusts and cores. The implication of superfluidity/superconductivity for equilibrium and dynamical neutron star states is that each…
Phase transitions of matter under changes of external environment such as temperature and magnetic field have attracted great interests to various quantum many-body systems. Several phase transitions must have occurred in neutron stars as…
We present the results of the first study of global oscillations of relativistic stars with both elastic crusts and interpenetrating superfluid components. For simplicity, we focus on the axial quasi-normal modes. Our results demonstrate…
R-modes in neutron stars with crusts are damped by viscous friction at the crust-core boundary. The magnitude of this damping, evaluated by Bildsten and Ushomirsky (BU) under the assumption of a perfectly rigid crust, sets the maximum spin…
We investigate the compressional modes of cold neutron stars with cores consisting of superfluid neutrons, superconducting protons and normal fluid electrons and muons, and crusts that contain superfluid neutrons plus a normal fluid of…
We suggest a specific new class of low-frequency g-modes in superfluid neutron stars. We determine the Brunt-Vaisala frequency for these modes and demonstrate that they can be unstable with respect to convection. The criterion for the…
We develop a general formalism to treat, in general relativity, the linear oscillations of a two-fluid star about static (non-rotating) configurations. Such a formalism is intended for neutron stars, whose matter content can be described,…
We have investigated an influence of the r-mode instability on hypercritically accreting ($\dot{M}\sim 1M_\odot {y}^{-1}$) neutron stars in close binary systems during their common envelope phases based on the scenario proposed by Bethe et…
Recent work has shown that differential rotation, producing large scale drifts of fluid elements along stellar latitudes, is an unavoidable feature of r-modes in the nonlinear theory. We investigate the role of this differential rotation in…
We re-visit the calculation of mode oscillations in the ocean of a rotating neutron star, which may be excited during thermonuclear X-ray bursts. Our present theoretical understanding of ocean modes relies heavily on the traditional…
We investigate the modal properties of inertial modes of rotating neutron stars with the core filled with neutron and proton superfluids, taking account of entrainment effects between the superfluids. In this paper, the entrainment effects…
Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is simulated assuming $^1$S$_0$ pairing of neutrons in the NS crust, and also $^1$S$_0$ pairing of protons and weak $^3$P$_2$ pairing of neutrons in…