共查询到20条相似文献，搜索用时 15 毫秒
1.
K. Shanthi 《Astrophysics and Space Science》1989,162(1):163-165
Explicit vacuum field equations in the general scalar-tensor theory of gravitation proposed by Nordtvedt are obtained with the aid of the most general conformally flat spherically-symmetric static space-time. It is shown that the most general conformally flat spherically-symmetric static solution of Nordtvedt-Barker vacuum field equations is simply the empty flat space-time of general relativity. 相似文献
2.
In this paper we have obtained general solution representing conformally-flat, non-static spherically-symmetric perfect fluid distribution in Einstein-Cartan theory. In particular, the solution has been also discussed in co-moving coordinates. The explicit expressions for pressure, density, expansion, rotation, shear and non-vanishing components of flow vector have also been found. 相似文献
3.
We present a conformally-flat metric in general relativity representing the gravitational field of a spherically-symmetric material distribution-radiating energy in the form of photons and neutrinos. A particular case of the solution is discussed and the corresponding expressions for mass function, linear dimension, and the luminosity have been derived. The solution seems to be physically sound as it corresponds to positive expressions for fluid pressure, fluid density, and radiation flux density. 相似文献
4.
D. R. K. Reddy 《Astrophysics and Space Science》1987,138(1):121-125
The Einstein field equations for an irrotational perfect fluid with pressurep, equal to energy density are studied when the space-time is conformally flat. The coordinate transformation to co-moving coordinates is discussed. The energy and Hawking-Penrose inequalities are studied. Static and non-static solutions of the field equations are obtained. It is interesting to note that in the static case the only spherically-symmetric conformally flat solution for self-gravitating fluid is simply the empty flat space-time of general relativity. 相似文献
5.
《Chinese Astronomy and Astrophysics》1983,7(1):58-61
In this paper we discuss the dynamical properties of a spinning body in a gravitational gauge theory containing torsion. Formulae are given for the precession of the Earth in the static spherically-symmetric field of the Sun and of the gyroscope. These formulae are valid for any model of gauge theory that includes torsion. 相似文献
6.
W. Walter Petry 《Astrophysics and Space Science》1988,140(2):407-419
Starting from the theory of gravitation in flat space-time of Petry (1981), the gravitational field of a static spherically-symmetric body is studied. Petry (1982) has shown that this field in the exterior of the body depends on a parameter which is fixed by the interior solution, i.e., it depends on the density of matter, the pressure, the equation of state, etc. If this parameter is small, the results for the well-known effects, i.e., redshift, deflection of light, perihelion shift, and radar time-delay, agree with those of general relativity. In this paper, we study these effects for larger values of this parameter. Furthermore, for sufficiently large positive values of the parameter, in the neighbourhood of the body the radial velocity of light can exceed several times the vacuum light-velocity. Therefore, the components of such an object can move away with velocities a few times greater than that of light in agreement with the observed superluminal velocities in extragalactic objects. 相似文献
7.
A class of spherically-symmetric cosmological models for space-time filled with infinitely conducting relativistic perfect fluids with constant magnetic permeability is developed for a specified choice of matter density and fluid pressure. Some salient features of all these solutions are discussed. 相似文献
8.
Vladimír Majerník 《Astrophysics and Space Science》1985,113(1):199-203
In the framework of Rastall's conservative program for the construction of gravitation theory we present a variant of modified classical gravitation theory based on Einstein's energy-mass equivalence principle. We pursue further the special-relativistic arguments and obtain a theory for the static spherically-symmetric gravitation field that is based only on the well-established physical principles and accounts for all experimental tests known in gravitation. Some astrophysical consequences of the modified classical gravitation theory (e.g., the non-existence of black holes, the creation of real particles in a strong gravitation field) are also discussed. 相似文献
9.
M. D. Roberts 《Astrophysics and Space Science》1993,200(2):331-335
It is known that the requirement of asymptotic flatness places restrictions on spherically-symmetric solutions to field equations. Here it is shown that the most general solution to the static spherically-symmetric massless scalar Einstein equations with zero cosmological constant is asymptotically flat; furthermore, the general solution is derived and shown to be identical to a solution previusly found by M. Wyman. 相似文献
10.
A static conformally flat spherically-symmetric perfect fluid cosmological model based on Lyra's modified Riemannian geometry is proposed. Some properties of the model are discussed. 相似文献
11.
Vladimir V. Sokolov 《Astrophysics and Space Science》1992,197(1):87-108
In the bounds of a theoretical scheme treating consistently gravitational interaction as dynamical (gauge) field in flat space-time, an expression was obtained for the density of energy-momentum-tension of gravitational field in vacuum around a collapsed object. A case was studied of an interacting static spherically-symmetric field of a collapsar in vacuum with taking into account of input of all the possible components (spin states of virtual gravitons) into the energy for the symmetric tensor of second rank
ik
. The radius of the sphere filled by matter for the collapsar of massM may achieve values up toGM/c
2. 相似文献
12.
The present Letter represents an exact, static, and spherically-symmetric solution of Einstein's field equations for a homogeneous perfect fluid core surrounded by a field of Zeldovich's fluid which is asymptotically homaloidal. 相似文献
13.
14.
Henry E. Kandrup 《Astrophysics and Space Science》1986,125(2):361-374
This paper uses existing techniques developed by Ipser, Thorne, and Kandrup to examine the stability of multi-component systems, with a distribution of masses, whose evolution is described by the collisionless or collisional Boltzmann equation.The principal conclusions are as follows: (1) All static, spherically-symmetric solutions to the collisionless equations, appropriate for a star cluster, are guaranteed to be stable with respect to spherically-symmetric disturbances, provided only that the population of stars is, for fixed mass, a decreasing function of the mean field energy. (2) If, furthermore, the static configuration has an isotropic distribution of momenta, it will also be stable towards nonradial perturbations. (3) The unique static solution to the collisional equations for a spherically-symmetric, spatially truncated configuration can be stable only if that configuration is a local entropy maximum. (4) A simple expression is obtained for the Jeans length for a system with an arbitrary isotropic distribution of momenta. 相似文献
15.
Vacuum field equations for the static and non-static plane-symmetric metric are obtained in self-creation theory of gravitation proposed by Barber (1982). It is shown that, in both static and non-static cases, the only plane-symmetric solution in vacuum is the empty flat space-time of Einstein's theory. It is observed that this result is quite different from that of the Brans-Dicke and other scalar-tensor theories of gravitation. 相似文献
16.
M. D. Roberts 《Astrophysics and Space Science》1988,147(2):321-327
Wyman's solution is the most general solution to the static spherically-symmetric Einstein massless scalar field equations. It is shown that it has no axial perturbation in which the scalar field is incremented, except in the case where the initial scalar field and the cross-metric increments are negligible. The one dimensional Schrödinger equation which governs axial metrix perturbations is produced. 相似文献
17.
Quasinormal modes of a black hole with quintessence-like matter and a deficit solid angle: scalar and gravitational perturbations 总被引：1，自引：0，他引：1
Ping Xi 《Astrophysics and Space Science》2009,321(1):47-51
In the previous paper (Li et al. in Phys. Lett. B 666:125–130, 2008), we show the solutions of Einstein equations with static spherically-symmetric quintessence-like matter surrounding a global
monopole. Furthermore, this monopole become a black hole with quintessence-like matter and a deficit solid angle when it is
swallowed by an ordinary black hole. We study its quasinormal modes by WKB method in this paper. The numerical results show
that both the real part of the quasinormal frequencies and the imaginary part decrease as the state parameter w, for scalar and gravitational perturbations. And we also show variations of quasinormal frequencies of scalar and gravitational
fields via different ε (deficit solid angel parameter) and different ρ
0 (density of static spherically-symmetric quintessence-like matter at r=1), respectively. 相似文献
18.
Ewa Rydzyńska 《Astrophysics and Space Science》1990,173(2):241-249
In this paper, new ideas from our previous paper (Rydzyska, 1989)-i.e., problems connected with the new equivalence principle-have been developed. It is conformed, that certain static particles from Bellert's space-time are equivalent to a free particle from classic Milne's space-time. Mention is made of the algebraic structure of Bellert's space-time from (Rydzyska, 1990b). The space-time interval in this space-time, and its connection with a probability and the physical meaning of this interval and probability, has been defined. In the last section we derive dynamical equations for Bellert's space-time, i.e., we do the foundations of Bellert's general relativity theory. 相似文献
19.
G. M. Webb 《Astrophysics and Space Science》1977,50(2):349-360
A non spherically-symmetric monoenergetic-point-source solution of the steady-state equation of transport for cosmic-rays in the interplanetary region, in which monoenergetic particles are released isotropically and continuously from a fixed heliocentric position is derived by a Laplace transform method. The solution is for a spherically-symmetric model of the propagating region incorporating anisotropic diffusion, with a diffusion tensor symmetric about the radial direction, and the solar wind velocity is radial and of constant speedV. The spherically-symmetric monoenergeticsource solution of Webb and Gleeson (1973) and of Toptygin (1973) is regained from the spherically-symmetric component of the point-source solution. 相似文献
20.
Qualitative behaviour of the trajectories of test bodies is investigated in the five-dimensional gravitation theory for the spherically-symmetric solution. The Binnet formula is obtained for the trajectory. The region of the existence of circular trajectories as well as the regions of their stability are specially investigated using the method of numerical calculations. The values of the free parameters in the five-dimensional gravitation theory are estimated for the solar system. 相似文献