共查询到20条相似文献，搜索用时 359 毫秒
1.
We present a solution to the Einstein field equations for a massless scalar field in a Bianchi type-V spacetime, which can be interpreted as a solution for a perfect fluid with the equation of state of stiff matter. This solution complements a solution previously given by us for an anisotropic fluid. 相似文献
2.
In a previous paper, a semi-analytical solution for the long-term motion of Pluto was presented. The present paper contains: (1) a comparison of the present solution with the solution by Williams and Benson; (2) a discussion of the effect of the near resonance between Pluto and Uranus; and, (3) a calculation of the librational period of the eccentricity, inclination and perihelion.The semi-analytical solution is shown to agree very closely with the long-term solution for Pluto obtained by Williams and Benson using numerical integration of the averaged equations of motion. A small difference between the two solutions is attributed to neglecting the eccentricity and inclination of Neptune in the semi-analytical solution. 相似文献
3.
Dieter Lorenz-Petzold 《Astrophysics and Space Science》1985,109(2):411-411
We wish to point out that the Brans-Dicke-Bianchi type-III vacuum solution recently given by Tiwari and Singh (1984) is not new. Moreover, the solution given has no correct Einstein limit, contrary to what is claimed by these authors. The Ellis-MacCallum vacuum solution in the Einstein case can be obtained from the Brans-Dicke solution first given by Lorenz-Petzold (1984a). 相似文献
4.
It is shown that the analytical solution of the equilibrium plasma equation which is a superposition of the axial-symmetric solution and the solution with helical symmetry can describe asymmetry of elements for a bipolar sunspot group. 相似文献
5.
Haruo Yoshida 《Celestial Mechanics and Dynamical Astronomy》1987,40(1):51-66
The straight-line collision solution in the anisotropic Kepler problem is extended to a periodic solution by means of Sundman's analytic continuation. It is shown that this collision periodic solution is always exponentially unstable. 相似文献
6.
In this note a new solution of the BD field equations, for a Bianchi type V space-time, is obtained. The solution has its general relativistic analogue. Some properties of the solution are also discussed. 相似文献
7.
Dieter Lorenz-Petzold 《Astrophysics and Space Science》1984,98(1):191-192
We wish to point out that the axialsymmetric Bianchi type I vacuum solution recently given by Ram, is wrong. Moreover, the correct solution is only a special case of the general triaxial Bianchi type I solution given by Ruban and Finkelstein. 相似文献
8.
Tang Ze-mei 《Chinese Astronomy and Astrophysics》1981,5(3):342-348
In this paper, the self-consistent density wave theory containing both a gaseous shock and a linear stellar density wave is studied, and a quasi-stable, tightly-wound, two-arm solution is obtained. The solution is convergent if the incomplete, linearized hydrodynamic equations are used, and the solution then gives the same dispersion relation as the local, asympotic solution, but the density and field profiles will be non-sinusoidal. The stellar wave will be unstable if the complete, linearized hydrodynamic equations are used. 相似文献
9.
D. Kramer 《Astronomische Nachrichten》1986,307(5):309-312
A class of stationary rigidly rotating perfect fluids in General Relativity is investigated. This class which is characterized by zero Simon tensor contains only the Wahlquist solution and its limits. It is shown how a recently given solution follows from the Wahlquist solution by a limiting procedure. 相似文献
10.
An exact solution of the vacuum Brans-Dicke field equations is obtained for the metric tensor of a spatially-homogeneous and anisotropic Bianchi type I configuration. The solution has no analogy in Einstein's theory for the layer values of the BD parameter. Some properties of the solution are discussed. 相似文献
11.
We present an exact solution of Einstein's equations for cosmological models of Bianchi type-II filled with string dust as the source for the gravitational field. The solution represents an expanding and anisotropic universe which would give essentially an empty universe for large time. Some kinematical properties of the solution are discussed. 相似文献
12.
Cantó Espresate Raga & D'Alessio 《Monthly notices of the Royal Astronomical Society》1998,296(4):1041-1044
The 'plasmon' solution of De Young & Axford describes the interaction between a high-velocity clump and the surrounding medium. Even though this solution is probably too simplistic, it has proven to be most useful in the study of diverse astrophysical flows. In the present paper, we discuss a more detailed solution of the plasmon problem, which includes the centrifugal effects of the environmental material flowing around the plasmon. We derive both numerical and approximate analytic solutions of this problem, and compare them with the analytic solution of De Young & Axford. 相似文献
13.
Jacques Henrard 《Celestial Mechanics and Dynamical Astronomy》1979,19(4):337-355
A new solution for the Main Problem on Lunar Theory is given. This solution maintains the advantages of an analytical solution and should be more accurate than previous analytical or numerical solutions. It contains the effects of the mass ratios which are often neglected in the definition of the Main Problem. 相似文献
14.
Reduction the secular solution to periodic solution in the generalized restricted three-body problem
Elbaz I. Abouelmagd M. E. Awad E. M. A. Elzayat Ibrahim A. Abbas 《Astrophysics and Space Science》2014,350(2):495-505
The aim of the present work is to find the secular solution around the triangular equilibrium points and reduce it to the periodic solution in the frame work of the generalized restricted thee-body problem. This model is generalized in sense that both the primaries are oblate and radiating as well as the gravitational potential from a belt. We show that the linearized equation of motion of the infinitesimal body around the triangular equilibrium points has a secular solution when the value of mass ratio equals the critical mass value. Moreover, we reduce this solution to periodic solution, as well as some numerical and graphical investigations for the effects of the perturbed forces are introduced. This model can be used to examine the existence of a dust particle near the triangular points of an oblate and radiating binary stars system surrounded by a belt. 相似文献
15.
The problem of diffuse reflection and transmission of solar radiation through a planetary atmosphere bounded from below by a reflecting surface is solved. The solution method based on rewriting the solution of the proposed problem in terms of the well known standard problem solution, where the planetary surface does not reflect. The solution of the standard problem can be found elsewhere or as we did by using the maximum entropy method. Numerical results for the angular radiation intensity and for the reflection and transmission coefficients are presented and compared with those obtained by Chandrasekhar's method. 相似文献
16.
In this paper an exact solution of the Brans-Dicke field equations in the presence of stiff matter is obtained for the Bianchi type-I cosmological space-time. The new solution represents an anisotropic homogeneous cosmological model which tends to anisotropic expansion. The behaviour of the solution near the singularities and late stages of the expansion is discussed. 相似文献
17.
This paper deals with the investigation of a closed form solution of a generalized fractional reaction-diffusion equation. The solution of the proposed problem is developed in a compact form in terms of the H-function by the application of direct and inverse Laplace and Fourier transforms. Fractional order moments and the asymptotic expansion of the solution are also obtained. 相似文献
18.
A closed-form first-order perturbation solution for the attitude evolution of a triaxial space object in an elliptical orbit is presented. The solution, derived using the Lie–Deprit method, takes into account gravity-gradient torque and is facilitated by an assumption of fast rotation of the object. The formulation builds on the earlier implementation of Lara and Ferrer, which assumes a circular orbit. The previously presented work—which assumes spin about an object’s axis of maximum inertia—is further extended by the explicit presentation of the transformations required to apply the solution to an object spinning about its axis of minimum inertia. Additionally, several numerical analyses are presented to more completely assess the utility of the solution. These studies (1) validate the elliptical solution, (2) assess the impact of varying the small parameter of the perturbation procedure, (3) analyze the assumption of fast rotation, and (4) apply the solution to the common and important scenario of a tumbling rocket body. 相似文献
19.
Alan H. Jupp 《Celestial Mechanics and Dynamical Astronomy》1974,9(1):3-20
It is well known that the equations governing the motion of a freely-rotating rigid body possess an exact analytical solution, involving Jacobi's elliptic functions. Andoyer (1923) and Deprit (1967) have shown that the problem may be very usefully reduced to a one-degree-of-freedom Hamiltonian system. When two of the body's principal moments of inertia are very nearly equal, the Hamiltonian system has the same form as the Ideal Resonance Problem. In earlier publications (Jupp, 1969, 1972, 1973), the author has constructed formal power-series solutions of the latter problem.In this article, the general solution of the Ideal Resonance Problem is employed to formulate a second-order formal series solution of the problem of a freely-rotating rigid body which has two of its principal moments of inertia differing by a small quantity. This solution is firstly expressed in terms of the mean elements, and then in terms of the initial conditions. The latter solution is global in nature being applicable over the whole phase plane. It is demonstrated that the exact solution and the second-order formal series solution, written in terms of the initial conditions, differ by terms of at most third order in the small parameter, over the whole domain of possible motions. This serves as an important check on the general results published in the earlier articles. 相似文献
20.
S. S. Sazhin 《Astrophysics and Space Science》1988,145(1):163-166
An analytical solution of the general plasma wave dispersion equation is obtained for the parameters close to those for which the numerical or analytical solution of this equation is known. This solution is further applied to parallel whistler-mode waves in an anisotropic plasma observed in the Earth's magnetosphere.Now at the Dept. of Physics, University of Sheffield, England. 相似文献