Thermal convection instability of liquid metals in magneto-hydrodynamics     

Rama Singhal  Krishna M. Srivastava 《Astrophysics and Space Science》1983,89(1):33-51

The problem of thermal convection instability of a horizontal layer of magnetized fluid has been studied to occur crystal growing under the effect of horizontal temperature gradient. In the study, the problem has been reduced to an eigen-value problem for a stream function. The dispersion relations for low viscosity fluid and high viscosity fluid respectively have been discussed analytically and some numerical results have been obtained. It is shown that the critical Rayleigh number and other its related constants for low viscosity fluid (i.e., mercury) are much differ than the high viscosity fluid (i.e., glycerol).  相似文献   

Nonlinear electrostatic drift Kelvin-Helmholtz instability     

Avadhesh C. Sharma  Krishna M. Srivastava 《Astrophysics and Space Science》1993,200(1):107-116

Nonlinear analysis of electrostatic drift Kelvin-Helmholtz instability is performed. It is shown that the analysis leads to the propagation of the weakly nonlinear dispersive waves and the nonlinear behaviour is governed by the nonlinear Burger's equation.  相似文献   

Eclipsing binary system AV Hydrae     

J. B. Srivastava  C. D. Kandpal 《Astrophysics and Space Science》1981,76(1):173-186

The eclipsing binary AV Hya has been observed photoelectrically inU, B andV filters on 15 nights. The primary eclipse appeared to be total with a totality of 23 min duration. A modified period of 0^d.6 834 062 has been obtained. Geometrical elements could only be determined for partial transit case.  相似文献   

Anisotropic propagation of magnetogasdynamic sonic waves in conducting and radiating atmosphere     

B. G. Verma  R. C. Srivastava  A. H. Khan 《Astrophysics and Space Science》1983,91(2):289-297

The propagation of sonic discontinuity in conducting and radiating atmosphere has been discussed under the influence of magnetic field. The velocity of sonic wave and its termination into shock wave has been obtained. We have also obtained the critical time at which sonic wave terminates into shock wave. There is significant effect of magnetic field on sonic velocity and its termination into shock wave.  相似文献   

An analysis of the light changes of the eclipsing binary XY ceti in the frequency-domain     

Srivastava  R. K. 《Astrophysics and Space Science》1987,138(1):197-207

The photoelectric observations of the eclipsing binary XY Ceti presented by us (see Srivastava and Padalia, 1975) have been analysed by Okazaki (1978) and Ramellaet al. (1980). They presented different sets of elements from the same set of our observations. This necessitated us to obtain the elements of XY Ceti again employing recent method of determination of elements.The revised geometrical elements of the eclipsing binary XY Ceti have been obtained by the method of Fourier analysis of the light changes in the frequency-domain, which was developed by Kopal (1979). These have been compared with our earlier (Srivastava and Padalia, 1975) results obtained by employing Russell and Merrill's (1952) method. The revised absolute dimensions of XY Ceti have been obtained using the spectroscopic elements given by Popper (1971), and the newly derived geometrical elements. The Roche radii have been derived to discuss the evolution of the system. The secondary component lies reasonably near to the Main Sequence, while the primary component falls above it. The evolutionary discussion indicates that the system is a detached one.  相似文献   

An exact similarity solution in radiation magneto-gas-dynamics for the flows behind a spherical shock wave     

J. P. Vishwakarma  R. C. Srivastava  Arun Kumar 《Astrophysics and Space Science》1987,129(1):45-52

An exact similarity solution for a spherical magnetogasdynamic shock is obtained in the case when radiation energy, radiation pressure and radiative heat flux are important. The total energy of the shock wave increase with time. We have shown that due to the magnetic field the flow variables are considerably changed. Also, due to increases in radiation pressure number the radiation flux is increased.  相似文献   

Eclipsing binary UW Bootis     

J. B. Srivastava  C. D. Kandpal 《Astrophysics and Space Science》1987,133(2):291-296

Photometric observations of primary minimum inU, B, andV filters have been discussed. The amplitude of variation in all the three filters is 0 ^m .66. We do not find variations in the period and its revised value is 1^d.0047115.  相似文献   

Propagation of exponential shock waves in magnetogasdynamics     

V. K. Singh  G. K. Srivastava 《Astrophysics and Space Science》1989,155(2):215-224

Self-similar flows of a perfect gas behind the cylindrical shock wave propagating exponentially in an atmosphere whose density varies inversely as the fourth power of shock radius are investigated. The effects of radiation flux has also been taken into consideration. The total energy of the wave is constant.  相似文献   

Spectral-luminosity classification,colour variations and suspected beta canis Majoris-type variability in IZ Persei     

R. K. Srivastava 《Astrophysics and Space Science》1987,132(1):125-139

The colour indices and the spectrum-luminosity classification of the eclipsing binary system IZ Persei have been presented for the first time. The colour indices of the system appear reddened. Applying the interstellar reddening corrections, the spectral-luminosity classes of the primary and the secondary components of IZ Per come out to be B2.5III-V and B5III-V, respectively. The averageB-V andU-B colour excesses come out to be 0 ^m .4 and 0 ^m .2, respectively. The colour indices show continuous variation throughout the cycle, and indicate the presence of intrinsic variability. Tentative analysis suggests that the primary component of IZ Per is a Beta Canis Majoris-type variable. The possibility of a shell has also been discussed.  相似文献   

CU Eridani — A suspected variable     

J. B. Srivastava  R. K. Srivastava 《Astrophysics and Space Science》1987,129(2):415-418

Photometric observations of CU Eridani, recently classified as non-variable, indicate it to be a variable star.  相似文献