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1.
The influence of the effect of entrainment of superconducting protons by superfluid neutrons on the distribution of neutron vortices in a rotating neutron star is investigated. It is shown that the proton vortex clusters generated by entrainment currents create the magnetic structure of a neutron vortex. The average magnetic field induction in a neutron vortex is calculated. The presence of the magnetic field of a neutron vortex considerably alters the radius of the vortex zone. The width of the vortex-free zone at the surface of the neutron star’s core increases, reaching macroscopic values on the order of several meters. This result considerably changes earlier concepts of the distribution of neutron vortices in a neutron star. Translated from Astrofizika, Vol. 43, No. 3, pp. 377-386, July–September, 2000.  相似文献   

2.
The Ginzburg-Landau equations are derived for the magnetic and gluomagnetic gauge fields in the color superconducting core of a neutron star containing a CFL-condensate of diquarks. The interaction of the diquark CFL-condensate with the magnetic and gluomagnetic gauge fields is taken into account. The behavior of the magnetic field in a neutron star is studied by solving the Ginzburg-Landau equations taking correct account of the boundary conditions, including the gluon confinement conditions. The magnetic field distribution in the quark and hadronic phases of a neutron star is found. It is shown that a magnetic field generated in the hadronic phase by the entrainment effect penetrates into the quark core in the form of quark vortex filaments because of the presence of screening Meissner currents. __________ Translated from Astrofizika, Vol. 50, No. 1, pp. 87–98 (February 2007).  相似文献   

3.
We adopt that in the interior of neutron stars both the proton and neutron superfluids are in the vortex state. Thus, in the superconducting core the magnetic field is expected to be organized in the form of quantized fluxoids. It is shown that fluxoids are buoyant. This gives rise to a rapid (5×104 yr) expulsion of the magnetic field out of the superconducting core to the subcrustal region, and a subsequent decay within the outer crust. The effect considered may be the physical reason why the characteristic decay-time of pulsar magnetic fields (106 yr) corresponds to the ohmic dissipation time within the neutron star crust. The intersection of two types of vortex lines with each other and its possible consequence for pulsars is briefly discussed.  相似文献   

4.
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.  相似文献   

5.
The Ginzburg-Landau equations are derived for the magnetic and gluomagnetic gauge fields of nonabelian semi-superfluid vortex filaments in color superconducting cores of neutron stars containing a diquark CFL condensate. The interaction of the diquark CFL condensate with the magnetic and gluomagnetic gauge fields is taken into account. The asymptotic values of the energies of these filaments are determined from the quantization conditions. It is shown that a lattice of semi-superfluid vortex filaments with a minimal quantum of circulation develops in the quark superconducting core during rotation of the star. The magnetic field in the core of this vortex is on the order of 1018 G. A cluster of proton vortices, which develops in the hadron phase surrounding every superfluid neutron vortex owing to an entrainment effect, creates new semi-superfluid vortex filaments with a minimal quantum of circulation in the quark superconducting core. Translated from Astrofizika, Vol. 51, No. 4, pp. 633–646 (November 2008).  相似文献   

6.
It is shown how to set up a mathematically elegant and fully relativistic superfluid model that can provide a realistic approximation (neglecting small anisotropies due to crust solidity, magnetic fields, etc., but allowing for the regions with vortex pinning) of the global structure of a rotating neutron star, in terms of just two independently moving constituents. One of these represents the differentially rotating neutron superfluid, while the other part represents the combination of all the other ingredients, including the degenerate electrons, the superfluid protons in the core, and the ions in the crust, the electromagnetic interactions of which will tend to keep them locked together in a state of approximately rigid rotation. Order of magnitude estimates are provided for relevant parameters such as the resistive drag coefficient.  相似文献   

7.
The vortex structure of the “npe” phase of neutron stars with a 3P2 superfluid neutron condensate of Cooper pairs is discussed. It is shown that, as the star rotates, superfluid neutron vortex filaments described by a unitary ordering parameter develop in the “npe” phase. The entrainment of superconducting protons by the rotating superfluid neutrons is examined. The entrainment effect leads to the appearance of clusters of proton vortices around each neutron vortex and generates a magnetic field on the order of 1012 G. 3P2 neutron vortex filaments combine with quark semi-superfluid vortex filaments at the boundary of the “npe” and “CFL” phases. At the boundary of the “Aen” and “npe” phases, they combine with 1S0 neutron vortex filaments. In this way, a unified vortex structure is formed. The existence of this structure and its collective elastic oscillations explain the observed oscillations in the angular rotation velocity of pulsars.  相似文献   

8.
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.  相似文献   

9.
G. Srinivasan et al. (1990) proposed a simple and elegant explanation for the reduction of the neutron star magnetic dipole moment during binary evolution leading to low mass X-ray binaries and eventually to millisecond pulsars: Quantized vortex lines in the neutron star core superfluid will pin against the quantized flux lines of the proton superconductor. As the neutron star spins down in the wind accretion phase of binary evolution, outward motion of vortex lines will reduce the dipole magnetic moment in proportion to the rotation rate. The presence of a toroidal array of flux lines makes this mechanism inevitable and independent of the angle between the rotation and magnetic axes. The incompressibility of the flux-line array (Abrikosov lattice) determines the epoch when the mechanism will be effective throughout the neutron star. Flux vortex pinning will not be effective during the initial young radio pulsar phase. It will, however, be effective and reduce the dipole moment in proportion with the rotation rate during the epoch of spindown by wind accretion as proposed by Srinivasan et al. The mechanism operates also in the presence of vortex creep.  相似文献   

10.
We review emission models of soft gamma-ray repeaters (SGRs) within the context of magnetized neutron star origins. Motivations for moderate field (1010–12G) versus ultrastrong field ( 5 × 1014G) neutron stars are considered. Implications for the astrophyiscal models are discussed.  相似文献   

11.
A model is constructed for the magnetic field of the star HD 2453, which has a very long rotation period (P=521d). It is found that the structure of the field corresponds to the model of a dipole shifted by r=0.09R from the center. The angle of inclination of the axis of the dipole to the axis of rotation, =5°; that is, the star is viewed almost from its equator of rotation and magnetic equator. This explains the low amplitude of the phase dependence of the magnetic field, Be(P), and the low amplitude of the photometric variability. The field at the magnetic poles is equal to Bp=+4400 and -7660 G. The magnetic field parameters turn out to be close to those obtained by Landstreet and Mathys assuming a dipole-quadrupole-octupole model. A Mercator map of the magnetic field distribution of HD 2453 is produced.  相似文献   

12.
We apply the model of flux expulsion from the superfluid and superconductive core of a neutron star, developed by Konenkov & Geppert, both to neutron star models based on different equations of state and to different initial magnetic field structures. Initially, when the core and the surface magnetic field are of the same order of magnitude, the rate of flux expulsion from the core is almost independent of the equation of state, and the evolution of the surface field decouples from the core field evolution with increasing stiffness. When the surface field is initially much stronger than the core field, the magnetic and rotational evolution resembles that of a neutron star with a purely crustal field configuration; the only difference is the occurrence of a residual field. In the case of an initially submerged field, significant differences from the standard evolution only occur during the early period of the life of a neutron star, until the field has been re-diffused to the surface. The reminder of the episode of submergence is a correlation of the residual field strength with the submergence depth of the initial field. We discuss the effect of the re-diffusion of the magnetic field on the difference between the real and the active age of young pulsars and on their braking indices. Finally, we estimate the shear stresses built up by the moving fluxoids at the crust–core interface and show that these stresses may cause crust cracking, preferentially in neutron stars with a soft equation of state.  相似文献   

13.
We discuss the nature of the various modes of pulsation of superfluid neutron stars using comparatively simple Newtonian models and the Cowling approximation. The matter in these stars is described in terms of a two-fluid model, where one fluid is the neutron superfluid, which is believed to exist in the core and inner crust of mature neutron stars, and the other fluid represents a conglomerate of all other constituents (crust nuclei, protons, electrons, etc.). In our model, we incorporate the non-dissipative interaction known as the entrainment effect, whereby the momentum of one constituent (e.g. the neutrons) carries along part of the mass of the other constituent. We show that there is no independent set of pulsating g-modes in a non-rotating superfluid neutron star core, even though the linearized superfluid equations contain a well-defined (and real-valued) analogue to the so-called Brunt–Väisälä frequency. Instead, what we find are two sets of spheroidal perturbations whose nature is predominately acoustic. In addition, an analysis of the zero-frequency subspace (i.e. the space of time-independent perturbations) reveals two sets of degenerate spheroidal perturbations, which we interpret to be the missing g-modes, and two sets of toroidal perturbations. We anticipate that the degeneracy of all these zero-frequency modes will be broken by the Coriolis force in the case of rotating stars. To illustrate this we consider the toroidal pulsation modes of a slowly rotating superfluid star. This analysis shows that the superfluid equations support a new class of r-modes, in addition to those familiar from, for example, geophysical fluid dynamics. Finally, the role of the entrainment effect on the superfluid mode frequencies is shown explicitly via solutions to dispersion relations that follow from a 'local' analysis of the linearized superfluid equations.  相似文献   

14.
We show that the crust–core interface in neutron stars acts as a potential barrier to the peripheral neutron vortices approaching the interface in the model in which these are coupled to the proton vortex clusters. This elementary barrier arises because of the interaction of vortex magnetic flux with the Meissner currents set up by the crustal magnetic field at the interface. The dominant part of the force is derived from the cluster–interface interaction. As a result of the stopping of the continuous neutron vortex current through the interface, angular momentum is stored in the superfluid layers in the vicinity of the crust–core interface during the interglitch period. Discontinuous annihilation of proton vortices at the boundary restores the neutron vortex current and spins up the observable crust on short time-scales, leading to a glitch in the spin characteristics of a pulsar.  相似文献   

15.
There is a 3P2 neutron superfluid region in NS (neutron star) interior. For a rotating NS the 3P2 superfluid region is like a system of rotating magnetic dipoles. It will give out electromagnetic radiation, which may provide a new heating mechanism of NSs. This mechanism plus some cooling agent may give a sound explanation to NS glitches.  相似文献   

16.
Formation enthalpies are calculated for a number of point-defect structures in solid neutron star matter at densities above the neutron-drip threshold. The enthalpies obtained show that an amorphous heterogeneous solid phase is formed at temperatures in a glass transition region, and is likely to persist as the star cools. Its structural differences from the homogeneous body-centred cubic lattice previously assumed make it necessary to reconsider predictions of neutron-star magnetic field evolution, and severely limit the role of conventional superfluid neutron vortex pinning in the interpretation of pulsar glitch phenomena.  相似文献   

17.
Collective elastic oscillations of a lattice of nonabelian quark semisuperfluid vortex filaments in the superfluid core of a rotating neutron star are examined. It is shown that in the incompressible fluid approximation, transverse long wavelength oscillations (Tkachenko oscillations) owing to shear deformation of the vortex lattice propagate in a plane perpendicular to the axis of rotation. The periods of these oscillations are consistent with rotational variations on the order of 100-1000 days observed in the pulsars PSR B0531+21 and PSR B1828-11. Translated from Astrofizika, Vol. 52, No. 1, pp. 165–169 (February 2009).  相似文献   

18.
The calculations of supernova explosion are made, using the one-dimensional nonstationary equations of magnetic hydrodynamics for the case of cylindrical symmetry. The energy source is supposed to be the rotational energy of the system (the neutron star in the centre and the surrounding envelope). The magnetic field plays the role of a mechanism of the transfer of rotational momentum. The calculations show that the envelope split up during the dynamical evolution of the system, the main part of the envelope joins the neutron star and becomes uniformly rotating with it, the outer part of the envelope (10% mass) expands with large velocity, carrying out a considerable part of rotational energy and rotational momentum.These results correspond qualitatively with the observational picture of supernovae explosions.  相似文献   

19.
Pulsars are presently believed to be rotating neutron stars with frozen-in magnetic fields. Because of the high density of neutron stars, general relativistic effects are important since they effect both the structure and stability of such stars. Besides this, the magnetic field outside the star is also affected. Instead of falling of asr (2+l) as in flat space, it is shown that each magnetic multipole varies as a hypergeometric function of radius. A closed form of these hypergeometric functions is given in terms of Legendre functions of the second kind. If the mass of a neutron star exceeds about 2.4m , the star becomes unstable and coliapses. For a quasistatically collapsing body, it is shown that the magnetic field seen by a distant observer vanishes as the radius approaches the gravitational radius.This work was supported in part by the Air Force Office of Scientific Research, Office of Aerospace Research under AFOSR Grant 70-1866.  相似文献   

20.
An inhomogeneous model neutron star with a variable density profile of the type 0(r)=c[1–(2/3)r2/R2]exp(–r2/R2) is considered, where c is the central density, R is the star's radius, and is the inhomogeneity parameter in the radial mass distribution. This parameterization adequately reproduces the results of numerical evolutionary calculations of the density profile and enables one to obtain in analytical form the parameters of hydrostatic equilibrium and the eigenmodes of nonradial oscillations of a nonrotating neutron star, modeled by a spherical mass of incompressible, inviscid liquid. It is shown that a characteristic manifestation of the star's inhomogeneity is the presence of a stable dipole f-mode, the lowest one in the spectrum of natural oscillations. The presence of this mode serves as a general and primary criterion that evidently distinguishes all inhomogeneous hydrodynamic models from the homogeneous Kelvin model, in which the quadrupole mode is the lowest stable mode. Estimates obtained for the periods of nonradial pulsations coincide with the periods of micropulses observed in the average pulse profiles of c-pulsars. This suggests that the detected variations in emission intensity in the range of micropulse duration (on the order of 10–4 sec) are associated with nonradial stellar oscillations.Translated from Astrofizika, Vol. 39, No. 3, pp. 475–488, July–September, 1996.  相似文献   

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