Relaxation of the Angular Velocity of the Vela Pulsar Following Its First Eight Glitches

The theory of the relaxation of pulsar angular velocity is compared with observational data for the first eight glitches of the Vela pulsar. Solutions of the inverse problem in relaxation theory are obtained in the regions of exponential and linear relaxation in the core of the neutron star. From these solutions, a distribution of vortices is found that results in the observed relaxation of the pulsar's angular velocity. It is shown that the pinning of neutron vortices plays the primary role in the region of exponential relaxation, while in the region of linear relaxation one must allow for the variation of the angular velocity of the superfluid component.     

Inverse Problem of the Theory of Relaxation of the Vela Pulsar's Angular Velocity after Glitches

A theory of the relaxation of pulsar angular velocity is compared with observational data for the first eight glitches of the Vela pulsar. The inverse problem of the theory of relaxation is considered and solutions of this problem in the regions of exponential and linear relaxation are found. General features in the distribution of neutron vortices in these regions immediately after a glitch are determined. It is shown that these properties may be related to the size of the glitch in pulsar angular velocity.     

Magnetic Field of a Neutron Star With Color Superconducting Quark Matter Core

The behaviour of the magnetic field of a neutron star with a superconducting quark matter core is investigated in the framework of the Ginzburg-Landau theory. We take into account the simultaneous coupling of the diquark condensate field to the usual magnetic and to the gluomagnetic gauge fields. We solve the Ginzburg-Landau equations by properly taking into account the boundary conditions, in particular, the gluon confinement condition. We found the distribution of the magnetic field in both the quark and hadronic phases of the neutron star and show that the magnetic field penetrates into the quark core in the form of quark vortices due to the presence of Meissner currents.     

Explosion of a Minimum-Mass Neutron Star within Relativistic Hydrodynamics

Astronomy Letters - The relativistic hydrodynamics equations are adapted for the spherically symmetric case and the Lagrangian form. They are used to model the explosive disruption of a...     

Accretion by a Neutron Star Moving at a High Kick Velocity in the Supernova Ejecta

1 INTRODUCTION The classical problem of spherical accretion onto a compact object, e.g., a black hole or a neutron star (NS), has been studied by many authors. A hydrodynamical solution was presented by Bondi 1952, who showed that inside a certain capture…     

Neutron Stars with a Quark Core. I. Equations of State

An extensive set of realistic equations of state for superdense matter with a quark phase transition is derived on the basis of the three equations of state for neutron matter and the eight variants of strange quark-gluon plasmas in the MIT quark bag model. The characteristics of the phase transitions are described and the calculated equations of state with a density jump are studied in detail.     

Constraining the Angular Momentum of the Sun with Planetary Orbital Motions and General Relativity

The angular momentum of a star is an important astrophysical quantity related to its internal structure, formation, and evolution. Helioseismology yields $S_{\odot}= 1.92\times10^{41}\ \mathrm{kg\ m^{2}\ s^{-1}}$ for the angular momentum of the Sun. We show how it should be possible to constrain it in a near future by using the gravitomagnetic Lense?CThirring effect predicted by General Relativity for the orbit of a test particle moving around a central rotating body. We also discuss the present-day situation in view of the latest determinations of the supplementary perihelion precession of Mercury. A fit by Fienga et al. (Celestial Mech. Dynamical Astron. 111, 363, 2011) of the dynamical models of several standard forces acting on the planets of the solar system to a long data record yielded milliarcseconds per century. The modeled forces did not include the Lense?CThirring effect itself, which is expected to be as large as from helioseismology-based values of S _??. By assuming the validity of General Relativity, from its theoretical prediction for the gravitomagnetic perihelion precession of Mercury, one can straightforwardly infer $S_{\odot}\leq0.95\times10^{41}\ \mathrm{kg\, m^{2}\, s^{-1}}$ . It disagrees with the currently available values from helioseismology. Possible sources for the present discrepancy are examined. Given the current level of accuracy in the Mercury ephemerides, the gravitomagnetic force of the Sun should be included in their force models. MESSENGER, in orbit around Mercury since March 2011, will collect science data until 2013, while BepiColombo, to be launched in 2015, should reach Mercury in 2022 for a year-long science phase: the analysis of their data will be important in effectively constraining S _?? in about a decade or, perhaps, even less.     

Structure of the Magnetic Field of a Neutron Star

The magnetic field distribution in the superfluid, spherical, hadronic core of a rotating neutron star, which consists of vortex and vortex-free zones, is investigated. Due to the effect of entrainment of superconducting protons by rotating superfluid neutrons, a nonuniform magnetic field, the average value of which is constant, is formed in the vortex zone of the neutron star, directed parallel to the star's axis of rotation. It is shown that at the stellar surface, near the equatorial plane, there is a vortex-free zone of macroscopic size in which there is no magnetic field. The magnetic field near the boundaries of the vortex-free zone falls off exponentially with depth into the interior of this zone. This result essentially alters earlier concepts about the magnetic field distribution in the superfluid hadronic core of a neutron star. Outside the hadronic core the magnetic field has a dipole character with a magnetic moment on the order of 10³⁰ g×cm³.     

广义相对论框架中的IAU时间尺度和参考系

简要地回顾和介绍了IAU时间尺度和参考系的历史和进展，其主要内容：（1）牛顿时空观和相对论时空观，（2）IAU各种时间尺度的历史演变和相互关系；（3）IAU的天文参考系，有关的最新决议,相对论框架下度规及其规范问题，四维时空中的空间1PN坐标变换，也介绍了一些有关工作，阐明了与IAU最新决议稍有不同的观点，指出目前IAU有关决议可能仍存在的某种程度上的不完善。     

Linear Wave Beams in the Crust of a Neutron Star

The propagation of axially symmetric wave beams near the equatorial plane of a neutron star is studied. These waves are excited by a spatially bounded perturbation in the form of a transverse magnetic field applied to the inner boundary of the crust of the star. For a small ratio of the perturbed to the unperturbed magnetic field, a linear theory can be employed to solve the evolution equation. This condition is satisfied in the crust plasma of a neutron star for typical radio luminosities of pulsars. The resulting simple, exact solution in the form of linear gaussian beams exists without additional conditions on the dissipation, dispersion, and narrowness of the beams, if the velocity c _n of these waves is constant. The latter requirement is well satisfied for the plasma in neutron star crusts. The width of the gaussian beam also depends weakly on position.     

Single X-ray Bursts and the Model of a Spreading Layer of Accreting Matter over the Neutron Star Surface

The excess of the rate of type I X-ray bursts over that expected when the matter fallen between bursts completely burns out in a thermonuclear explosion which is observed in bursters with a high persistent luminosity (4 × 10³⁶ ? L_X ? 2 × 10³⁷ erg s^?1) is explained in terms of the model of a spreading layer of matter coming from the accretion disk over the neutron star surface. In this model the accreting matter settles to the stellar surface mainly in two high-latitude ring zones. Despite the subsequent spreading of matter over the entire star, its surface density in these zones turns out to be higher than the average one by 2–3 orders of magnitude, which determines the predominant ignition probability. The multiple events whereby the flame after the thermonuclear explosion in one ring zone (initial burst) propagates through less densematter to another zone and initiates a second explosion in it (recurrent burst) make a certain contribution to the observed excess of the burst rate. However, the localized explosions of matter in these zones, after which the burning in the zone rapidly dies out without affecting other zones, make a noticeably larger contribution to the excess of the burst rate over the expected one.     

Saa有挠引力模型下慢旋转磁中子星的电磁场

导出在Saa有挠引力模型下慢旋转磁中子星电磁场所满足的方程，并研究其外部解，得出如下结论：其一，选规范．A^0=0，电磁场存在某种形式的特解；其二，选规范A^0≠0，电磁场根本不存在此特解．故可通过观测中子星外部电磁场的形式判断挠率是否存在．     

Angular velocity glitches of the Vela pulsar in a model with “centrifugal buoyancy” of vortices

The forces acting on the solid crust of a differentially rotating neutron star are examined when a nonuniform excess of chemical potential exists. The resultant of the external forces, a stress force, is expressed in terms of a centrifugal buoyancy force and the deformation of the star’s crust under the action of this force is calculated. It is shown that there is a region within the star where the resulting stresses lead to fracture of the crust when the difference in the angular velocities of the superfluid and normal components reaches a critical value. The “centrifugal buoyancy” mechanism for generating a glitch is used to estimate the parameters of glitches in the Vela pulsar. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 183–197 (May 2007).     

Evolution of Pulsars with Energy Release in the Superfluid Core of a Neutron Star

The effect of a neutron-proton vortex system on the rotation dynamics of neutron stars is examined. The dynamics of the motion of a two component superfluid system in the core of a neutron star yields an equation for the evolution of the pulsar's rotation period. The spin down of the star owing to energy release at the core boundary, which is associated with a contraction of the length of the neutron vortex as it moves radially and magnetic energy of the vortical cluster is released, is taken into account. Evolutionary curves are constructed for pulsars with different magnetic fields and stellar radii. For certain values of the coefficient of friction between the superfluid and normal components in the core of the neutron star, at the end of its evolution a radio pulsar may become an anomalous x-ray pulsar or a source of soft gamma radiation with a period on the order of 10 seconds.     

Production of Heavy Elements during the Explosion of a Low-Mass Neutron Star in a Close Binary

Astronomy Letters - The nucleosynthesis of heavy elements in the scenario for the evolution of a close binary of neutron stars differing greatly in mass is considered. In contrast to the scenario...     

吸积盘与恒星在星云盘中形成时的角动量损失

本文根据吸秘盘理论与天文观测结果,给出一个恒星在星云盘中形成的模型.通过计算角动量方程,获得了质量定常分布ρ(r)～r_(-β)(β=0,1,2)时的一般性解.对1M恒星的数值解表明:恒星在转动磁化的星云盘中形成时,角动量确实发生了巨大转移;并且,β=2的解能较满意地解释太阳系的角动量奇异性.