RADIATING GRAVITATIONAL COLLAPSE WITH SHEAR REVISITED

2003 ◽  
Vol 12 (06) ◽  
pp. 1131-1155 ◽  
Author(s):  
R. CHAN
Keyword(s):  
Black Hole ◽  
Heat Flow ◽  
Gravitational Collapse ◽  
Total Mass ◽  
Naked Singularity ◽  
Radial Heat Flow ◽  
Radial Heat ◽  
Radiating Star ◽  
Shear Motion ◽  
Final Evolution

A model is proposed for a collapsing radiating star consisting of a fluid with shear motion undergoing radial heat flow with outgoing radiation. The pressure of the star, at the beginning of the collapse, is isotropic but due to the presence of the shear motion of the fluid the pressure becomes more and more anisotropic. The radial and temporal behaviors of the density, the pressure, the total mass, the luminosity, the effective adiabatic index and the Kretschmann scalar are analyzed for a star with 6 M⊙. The final evolution is a star that radiates all its mass during the collapse, and thus, neither forming a black hole, as in the previous model, nor a naked singularity.

RADIATING GRAVITATIONAL COLLAPSE WITH SHEAR VISCOSITY AND BULK VISCOSITY

2004 ◽  
Vol 13 (08) ◽  
pp. 1727-1752 ◽  
Author(s):  
P. C. NOGUEIRA ◽  
R. CHAN
Keyword(s):  
Heat Flow ◽  
Viscous Fluid ◽  
Gravitational Collapse ◽  
Bulk Viscosity ◽  
Shear Viscosity ◽  
Outgoing Radiation ◽  
Radial Heat Flow ◽  
Radial Heat ◽  
Radiating Star ◽  
Time Density

A model of a collapsing radiating star consisting of a fluid with shear viscosity and bulk viscosity undergoing radial heat flow with outgoing radiation is studied. This kind of fluid is the most general viscous fluid we can have. The pressure of the star, at the beginning of the collapse, is isotropic but, due to the presence of the shear viscosity and the bulk viscosity, the pressure becomes more and more anisotropic. The radial and temporal behaviors of the density, pressure, mass, luminosity, the effective adiabatic index and the Kretschmann scalar are analyzed. The collapsing time, density, mass, luminosity and Kretschmann scalar of the star do not depend on the viscosity of the fluid (nor the shear viscosity and neither the bulk viscosity).

NON-ADIABATIC GRAVITATIONAL COLLAPSE OF A SUPERDENSE STAR

2010 ◽  
Vol 19 (12) ◽  
pp. 1889-1904 ◽  
Author(s):  
SANJAY SARWE ◽  
RAMESH TIKEKAR
Keyword(s):  
Black Hole ◽  
Heat Flow ◽  
Gravitational Collapse ◽  
Adiabatic Shear ◽  
Dissipative Forces ◽  
Superdense Stars ◽  
Superdense Star ◽  
Radiating Star ◽  
Spheroidal Geometry ◽  
Relativistic Equations

The relativistic equations governing the non-adiabatic shear-free collapse of massive superdense stars in the presence of dissipative forces producing heat flow in the background of space–times of the Vaidya–Tikekar ansatz with associated physical three-spaces that have the three-spheroidal geometry are formulated. It is shown how the system can be used to examine the development and progress of the collapse during subsequent epochs until the radiating star becomes a black hole.

EXACT NONSPHERICAL RADIATING COLLAPSE

2007 ◽  
Vol 22 (16n17) ◽  
pp. 2945-2960 ◽  
Author(s):  
S. G. GHOSH ◽  
D. W. DESHKAR
Keyword(s):  
Heat Flow ◽  
Junction Conditions ◽  
Local Conservation ◽  
Plane Symmetric ◽  
Radial Heat Flow ◽  
Symmetric Version ◽  
Conservation Of Momentum ◽  
Radial Heat ◽  
Vaidya Solution ◽  
Radiating Star

We study the junction conditions for a nonspherical collapsing radiating star consisting of a shearing fluid undergoing radial heat flow with outgoing radiation. Radiation of the system is described by the plane symmetric version of the Vaidya solution. Junction conditions which match the collapse solutions to an exterior Vaidya metric show that, at the boundary, the pressure is proportional to the magnitude of the heat flow vector. Physical quantities, analogous to spherical symmetry related to the local conservation of momentum and surface redshift, are also obtained. Finally, exact gravitational collapse solutions, for both shear and shear-free cases, have been obtained by integrating a field equation.

scholarly journals NONSTATIC CHARGED BTZ-LIKE BLACK HOLES IN N+1 DIMENSIONS

2012 ◽  
Vol 21 (03) ◽  
pp. 1250022 ◽  
Author(s):  
SUSHANT G. GHOSH
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Collapse ◽  
Naked Singularity ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Btz Black Hole ◽  
Sitter Spacetime ◽  
Apparent Horizons ◽  
Sitter Background

We find an exact nonstatic charged BTZ-like solutions, in (N+1)-dimensional Einstein gravity in the presence of negative cosmological constant and a nonlinear Maxwell field defined by a power s of the Maxwell invariant, which describes the gravitational collapse of charged null fluid in an anti-de Sitter background. Considering the situation that a charged null fluid injects into the initially an anti-de Sitter spacetime, we show that a black hole form rather than a naked singularity, irrespective of spacetime dimensions, from gravitational collapse in accordance with cosmic censorship conjecture. The structure and locations of the apparent horizons of the black holes are also determined. It is interesting to see that, in the static limit and when N = 2, one can retrieve 2+1 BTZ black hole solutions.

GRAVITATIONAL COLLAPSE OF A SELF-INTERACTING SCALAR FIELD

2007 ◽  
Vol 22 (01) ◽  
pp. 65-74 ◽  
Author(s):  
RITUPARNO GOSWAMI ◽  
PANKAJ S. JOSHI
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Gravitational Collapse ◽  
Energy Condition ◽  
Dynamical Evolution ◽  
Naked Singularity ◽  
Cosmic Censorship ◽  
Weak Energy Condition ◽  
Scalar Field Models ◽  
Cosmic Censorship Conjecture

We construct and study here a class of collapsing scalar field models with a nonzero potential. The weak energy condition is satisfied by the collapsing configuration and it is shown that the end state of collapse could be either a black hole or a naked singularity. It is seen that physically it is the rate of collapse that governs these outcomes of the dynamical evolution. The implications for the cosmic censorship conjecture are discussed.

Measurement of effective thermal conductivity of lithium metatitanate pebble beds by steady-state radial heat flow method

2021 ◽  
Vol 172 ◽  
pp. 112854
Author(s):  
Maulik Panchal ◽  
Vrushabh Lambade ◽  
Vimal Kanpariya ◽  
Harsh Patel ◽  
Paritosh Chaudhuri
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Flow ◽  
Effective Thermal Conductivity ◽  
Flow Method ◽  
Radial Heat Flow ◽  
Radial Heat

Thermal Conductivity of Uranium Dioxide from -57o to 1100oC by a Radial Heat Flow Technique

1965 ◽  
Vol 48 (6) ◽  
pp. 297-305 ◽  
Author(s):  
T. G. GODFREY ◽  
W. FULKERSON ◽  
T. G. KOLLIE ◽  
J. P. MOORE ◽  
D. L. McELROY
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Uranium Dioxide ◽  
Radial Heat Flow ◽  
Radial Heat
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