Plane-symmetric universes in general relativity     

T. Singh  R. S. Srivastava 《Astrophysics and Space Science》1987,132(1):113-124

Plane-symmetric solutions of Einstein's field equations in vacuum, in the presence of electromagnetic fields and with cosmological constant are explored in null coordinates. The gravitational field of an infinite plane (uncharged and charged both) is thus obtained in a simple and systematic way. The method adopted for these solutions has possibilities of generalization.  相似文献   

A self-similar flow of self-gravitating gas behind a shock wave with radiation heat flux,I     

J. B. Singh  P. R. Vishwakarma 《Astrophysics and Space Science》1983,90(1):153-159

Self-similar flows of self-gravitating gas behind the spherical shock wave propagating in a non-uniform atmosphere at rest, taking radiation heat flux into consideration, are investigated. The total energy of the wave is non-constant and can be made to vary slowly with time.  相似文献   

Adiabatic radial pulsations of a composite stellar model     

Manmohan Singh  Sudha Rani Agarwal 《Astrophysics and Space Science》1983,94(2):351-359

Small adiabatic radial oscillations of composite models have been investigated. The effect of central condensation ρ_c√ρ on the period of pulsation have also been examined. In has been shown that the second moment of mass concentration characterize the periods of pulsation more effectively than central condensation.  相似文献   

X-rays from supernovae remants 3C 400.2 (≡ G53.7-2.2) and MSH 15-56     

P. C. Agrawal  G. R. Riegler  K. P. Singh 《Astrophysics and Space Science》1983,89(2):279-283

Detection of two new soft X-ray sources and their identification with the supernova remnants (RNRs) 3C400.2 and MSH 15-56, is reported. From the observed X-ray flux in the 0.7–2.0 keV energy range, the X-ray luminosity of 3C400.2 is derived to be in the range of (2.7–5.3)×10³⁵ ergs s^?1 and that of MSH 15-56 in the range of (0.9–1.6)×10³⁵ ergs s^?1. If we use the standard adiabatic shockwave model for the SNR's, an age of ～(1.4–3.2)×10⁴ yr is derived for 3C400.2 whereas MSH 15-56 is found to be younger of an age of (5–10)×10³ yr.  相似文献   

Unsteady isothermal flow of a gas behind an exponential shock in magnetogasdynamics     

J. B. Singh  P. R. Vishwakarma 《Astrophysics and Space Science》1983,95(1):111-116

A self-similar flow of a perfect gas behind a strong shock driven out by a propelling contact discontinuity surface moving with time according to an exponential law in the presence of axial component of the magnetic field is investigated. The flow between the shock and the inner-expanding surface is assumed to be isothermal. The infinite electrically conductive and uniform medium has been taken into consideration.  相似文献   

An anisotropic cosmological model in Brans-Dicke theory     

T. Singh  L. N. Rai  Tarkeshwar Singh 《Astrophysics and Space Science》1983,96(1):95-105

Solutions of Brans-Dicke field equations are obtained when the source of the gravitational field is a perfect fluid with pressure equal to energy density and the metric is cylindrically symmetric of Marder-type. Various physical and geometrical properties of the model have been discussed. Finally the solutions have been transformed to the original form of Brans-Dicke (1961) theory and then through unit transformation to a general form.  相似文献   

An approximate analytical solution for self-isothermal flow behind a radiation driven shock wave,II     

J. B. Singh 《Astrophysics and Space Science》1983,95(2):299-303

An analytical solution for a self-similar isothermal flow behind a radiation driven shock wave in non-uniform medium at rest is investigated using the method of Laumbach and Probstein (1969).  相似文献   

Equatorial propagation of axisymmetric magnetogasdynamic shocks with increasing energy,I     

J. B. Singh 《Astrophysics and Space Science》1983,92(1):191-195

A self-similar solution, for the equatorial propagation of axisymmetric point explosion into an inhomogeneous ideal gas permeated by a current-free azimuthal magnetic field, are obtained. The model has been considered here in which the magnetic field is proportional tor ^?1, but the total energy of the wave is of the increasing order, not constant.  相似文献   

LRS Bianchi type-V universes filled with matter and radiation     

S. R. Roy  J. P. Singh 《Astrophysics and Space Science》1983,96(2):303-312

In this paper we have investigated some LRS Bianchi type-V cosmologicla models representing a viscous fluid distribution with a null electromagnetic field and streaming neutrinos. Various physical and kinematical features of these models have also been explored.  相似文献   

Heat and mass transfer in rotating fluid with Hall current,I     

H. L. Agrawal  P. C. Ram  V. Singh 《Astrophysics and Space Science》1983,96(2):245-254

Hall effects on the hydromagnetic free convection resulting from the combined effects of thermal and mass diffusion of an electrically conducting liquid past an infinite vertical porous plate in a rotating system have been analysed. The expressions for the mean velocity, mean temperature in the boundary layer and the mean skin friction, the mean rate of heat transfer on the plate are derived. The effects of magnetic parameterM, Hall parameterm, Schmidt number Sc, and Ekman numberE on the flow field, are discussed with the help of graphs and tables.  相似文献