Junction conditions for spherically symmetric matter in co-moving co-ordinates

1969 ◽  
Vol 60 (2) ◽  
pp. 254-260 ◽  
Author(s):  
C. Leibovitz
Keyword(s):  
Spherically Symmetric ◽  
Junction Conditions

Five-dimensional spherical gravitational collapse of anisotropic fluid with cosmological constant

2017 ◽  
Vol 14 (02) ◽  
pp. 1750025 ◽  
Author(s):  
Suhail Khan ◽  
Hassan Shah ◽  
Ghulam Abbas
Keyword(s):  
Cosmological Constant ◽  
Apparent Horizon ◽  
Physical Significance ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Hole Size ◽  
Junction Conditions ◽  
De Sitter ◽  
Positive Cosmological Constant ◽  
Exterior Regions

Our aim is to study five-dimensional spherically symmetric anisotropic collapse with a positive cosmological constant (PCC). For this purpose, five-dimensional spherically symmetric and Schwarzschild–de Sitter metrics are chosen in the interior and exterior regions respectively. A set of junction conditions is derived for the smooth matching of interior and exterior spacetimes. The apparent horizon is calculated and its physical significance is studied. It comes out that the whole collapsing process is influenced by the cosmological constant. The collapsing process under the influence of cosmological constant slows down and black hole size also reduced.

scholarly journals EXPANSIONFREE FLUID EVOLUTION AND SKRIPKIN MODEL IN f(R) THEORY

2011 ◽  
Vol 20 (11) ◽  
pp. 2239-2252 ◽  
Author(s):  
M. SHARIF ◽  
H. RIZWANA KAUSAR
Keyword(s):  
General Relativity ◽  
The Self ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Dynamical Equations ◽  
Constant Energy ◽  
Isotropic Pressure ◽  
Symmetric Star ◽  
Constant Energy Density ◽  
General Influence

We consider the modified f(R) theory of gravity whose higher-order curvature terms are interpreted as a gravitational fluid or dark source. The gravitational collapse of a spherically symmetric star, made up of locally anisotropic viscous fluid, is studied under the general influence of the curvature fluid. Dynamical equations and junction conditions are modified in the context of f(R) dark energy and by taking into account the expansionfree evolution of the self-gravitating fluid. As a particular example, the Skripkin model is investigated which corresponds to isotropic pressure with constant energy density. The results are compared with corresponding results in General Relativity.

Discontinuities in spherically symmetric gravitational fields and shells of radiation

1958 ◽  
Vol 248 (1254) ◽  
pp. 404-414 ◽  
Keyword(s):  
Boundary Conditions ◽  
Spherical Shell ◽  
Previous Treatment ◽  
Empty Space ◽  
Point Of View ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Metric Tensor ◽  
Gravitational Fields

Boundary conditions at a 3-space of discontinuity ∑ are considered from the point of view of Lichnerowicz. The validity of the O’Brien—Synge junction conditions is established for co-ordinates derivable from Lichnerowicz’s ‘admissible co-ordinates’ by a transformation which is uniformly differentiable across ∑. The co-ordinates r , θ , ϕ , t , used by Schwarzschild and most later authors when dealing with spherically symmetric fields, are shown to be of this type. In Schwarzschild’s co-ordinates, the components of the metric tensor can always be made continuous across Ʃ, and simple relations are derived connecting the jumps in their first derivatives. A spherical shell of radiation expanding in empty space is examined in the light of the above ideas, and difficulties encountered by Raychaudhuri in a previous treatment of this problem are cleared up. A particular model is then discussed in some detail.

scholarly journals SPHERICALLY SYMMETRIC THICK BRANES IN VACUUM

2004 ◽  
Vol 19 (27) ◽  
pp. 4687-4694 ◽  
Author(s):  
MASSOUD BORHANI ◽  
REZA MANSOURI ◽  
SAMAD KHAKSHOURNIA
Keyword(s):  
Finite Thickness ◽  
Equation Of Motion ◽  
Space Time ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Bulk Space ◽  
Thick Branes

We consider a spherical thick 3-brane immersed in a five-dimensional bulk space–time. We demonstrate how the thick brane equation of motion expanded in powers of the thickness of the brane can be obtained from the expected junction conditions on the boundaries of thick brane with the two embedding space–times. It is shown that the finite thickness corrections lead to a faster collapse of the brane in the vacuum.

Junction conditions on null hypersurfaces for spherically symmetric metrics

1991 ◽  
Vol 32 (6) ◽  
pp. 1537-1540
Author(s):  
Zu‐hui Fan ◽  
Zhi‐quan Kuang ◽  
Can‐bin Liang ◽  
Yun‐qiang Yu
Keyword(s):  
Spherically Symmetric ◽  
Junction Conditions ◽  
Null Hypersurfaces ◽  
Symmetric Metrics

THE ROLE OF THE ELECTROMAGNETIC FIELD IN DISSIPATIVE COLLAPSE

2013 ◽  
Vol 22 (14) ◽  
pp. 1350087 ◽  
Author(s):  
S. THIRUKKANESH ◽  
M. GOVENDER
Keyword(s):  
Electromagnetic Field ◽  
Evolution Equation ◽  
Temporal Evolution ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Symmetric Spacetime ◽  
Charged Case ◽  
Spherically Symmetric Spacetime

In this paper, we investigate the effect of charge on the collapse of a radiating, shearing sphere. The junction conditions required for the smooth matching of a general spherically symmetric spacetime (in the absence of rotation) to the exterior Vaidya–Reissner–Nordström leads to a temporal evolution equation at the boundary of the collapsing star. We are in a position to integrate these equations in the presence of charge and shear. The solutions obtained here are new and generalize recent treatments of dissipative, shearing collapse to the charged case.

scholarly journals Radiating composite stars with electromagnetic fields

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Sunil D. Maharaj ◽  
Byron P. Brassel
Keyword(s):  
Charge Distribution ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
External Observer ◽  
Composite Field ◽  
Special Cases ◽  
Radiating Star ◽  
Special Case ◽  
Internal Charge ◽  
Null String

AbstractWe derive the junction conditions for a general spherically symmetric radiating star with an electromagnetic field across a comoving surface. The interior consists of a charged composite field containing barotropic matter, a null dust and a null string fluid. The exterior atmosphere is described by the generalised Vaidya spacetime. We generate the boundary condition at the stellar surface showing that the pressure is determined by the interior heat flux, anisotropy, null density, charge distribution and the exterior null string density. A new physical feature that arises in our analysis is that the surface pressure depends on the internal charge distribution for generalised Vaidya spacetimes. It is only in the special case of charged Vaidya spacetimes that the matching interior charge distribution is equal to the exterior charge at the surface as measured by an external observer. Previous treatments, for neutral matter and charged matter, arise as special cases in our treatment of composite matter.

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