Dissipative collapse of a Karmarkar star

2020 ◽  
Vol 35 (20) ◽  
pp. 2050164 ◽  
Author(s):  
M. Govender ◽  
A. Maharaj ◽  
Ksh. Newton Singh ◽  
Neeraj Pant
Keyword(s):  
Stellar Structure ◽  
Spherically Symmetric ◽  
Isotropic Coordinates ◽  
Radial Heat ◽  
Radiating Star ◽  
Physical Tests ◽  
Dynamical Nature ◽  
Radial Heat Flux ◽  
Radiative Collapse ◽  
Static Core

In this paper, we employ the Karmarkar condition to model a spherically symmetric radiating star undergoing dissipative gravitational collapse within the framework of classical general relativity. The collapse ensues from an initial static core satisfying the Karmarkar condition in isotropic coordinates and proceeds nonadiabatically by emitting energy in the form of a radial heat flux to the exterior Vaidya spacetime. We show that the dynamical nature of the collapse is sensitive to the initial static configuration that inherently links the embedding to the final remnant. Our model considered several physical tests on how an initially static stellar structure onset to a radiative collapse.

scholarly journals A perturbative approach to the time-dependent Karmarkar condition

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Megandhren Govender ◽  
Wesley Govender ◽  
Kevin P Reddy ◽  
Sunil D Maharaj
Keyword(s):  
Boundary Condition ◽  
Heat Flux ◽  
Gravitational Collapse ◽  
Time Dependent ◽  
Perturbative Approach ◽  
Radial Heat ◽  
Radiating Star ◽  
Static Regime ◽  
Radial Heat Flux ◽  
Static Core

AbstractIn this work we employ a perturbative approach to study the gravitational collapse of a shear-free radiating star. The collapse proceeds from an initial static core satisfying the time-independent Karmarkar condition and degenerates into a quasi-static regime with the generation of energy in the form of a radial heat flux. The time-dependent Karmarkar condition is solved together with the boundary condition to yield the full gravitational behaviour of the star. Our model is subjected to rigorous regularity, causality and stability tests.

The influence of an equation-of-state during radiative collapse

2016 ◽  
Vol 26 (07) ◽  
pp. 1750065 ◽  
Author(s):  
M. Govender ◽  
R. S. Bogadi ◽  
S. D. Maharaj
Keyword(s):  
Heat Flux ◽  
Equation Of State ◽  
State Parameter ◽  
Hydrostatic Equilibrium ◽  
Temperature Profiles ◽  
Equation Of State Parameter ◽  
Radial Heat ◽  
Radiating Star ◽  
Radial Heat Flux ◽  
Radiative Collapse

We study the role played by an equation-of-state during gravitational collapse of a radiating star. Starting from an initially static matter configuration obeying a linear equation-of-state, the star loses hydrostatic equilibrium and undergoes dissipative collapse in the form of a radial heat flux. We show that the equation-of-state parameter plays an important role in determining the temperature profiles of the collapsing body.

scholarly journals Study of charged compact stars with class 1 metric under general relativity

2019 ◽  
Vol 97 (12) ◽  
pp. 1323-1331 ◽  
Author(s):  
S.K. Maurya ◽  
S. Roy Chowdhury ◽  
Saibal Ray ◽  
B. Dayanandan
Keyword(s):  
General Relativity ◽  
Compact Star ◽  
Space Time ◽  
Electron Cloud ◽  
Compact Stars ◽  
Stellar Structure ◽  
Spherically Symmetric ◽  
Class 1 ◽  
Maxwell Space ◽  
Physical Tests

In the present paper we study compact stars under the background of Einstein–Maxwell space–time, where the 4-dimensional spherically symmetric space–time of class 1 along with the Karmarkar condition has been adopted. The investigations, via the set of exact solutions, show several important results, such as (i) the value of density on the surface is finite; (ii) due to the presence of the electric field, the outer surface or the crust region can be considered to be made of electron cloud; (iii) the charge increases rapidly after crossing a certain cutoff region (r/R ≈ 0.3); and (iv) the avalanche of charge has a possible interaction with the particles that are away from the center. As the stellar structure supports all the physical tests performed on it, therefore the overall observation is that the model provides a physically viable and stable compact star.

scholarly journals THE ROLE OF SHEAR IN DISSIPATIVE GRAVITATIONAL COLLAPSE

2014 ◽  
Vol 23 (02) ◽  
pp. 1450013 ◽  
Author(s):  
M. GOVENDER ◽  
K. P. REDDY ◽  
S. D. MAHARAJ
Keyword(s):  
Hydrostatic Equilibrium ◽  
The Core ◽  
Radial Heat ◽  
Free Case ◽  
Radiating Star ◽  
Heat Transport Equation ◽  
Physical Features ◽  
Radial Heat Flux ◽  
Collapse Process

In this paper, we investigate the physics of a radiating star undergoing dissipative collapse in the form of a radial heat flux. Our treatment clearly demonstrates how the presence of shear affects the collapse process; we are in a position to contrast the physical features of the collapsing sphere in the presence of shear with the shear-free case. By employing a causal heat transport equation of the Maxwell–Cattaneo form we show that the shear leads to an enhancement of the core temperature thus emphasizing that relaxational effects cannot be ignored when the star leaves hydrostatic equilibrium.

scholarly journals Collapse of a Relativistic Self-Gravitating Star with Radial Heat Flux: Impact of Anisotropic Stresses

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ranjan Sharma ◽  
Shyam Das
Keyword(s):  
Heat Flux ◽  
Simple Model ◽  
Heat Flow ◽  
Spherically Symmetric ◽  
Local Anisotropy ◽  
Evolving Systems ◽  
Radial Heat Flow ◽  
Radial Heat ◽  
Radial Heat Flux ◽  
Collapse Rate

We develop a simple model for a self-gravitating spherically symmetric relativistic star which begins to collapse from an initially static configuration by dissipating energy in the form of radial heat flow. We utilize the model to show how local anisotropy affects the collapse rate and thermal behavior of gravitationally evolving systems.

scholarly journals NONADIABATIC SPHERICAL COLLAPSE WITH A TWO-FLUID ATMOSPHERE

2013 ◽  
Vol 22 (07) ◽  
pp. 1350049 ◽  
Author(s):  
M. GOVENDER
Keyword(s):  
Heat Flux ◽  
Heat Transport ◽  
Line Element ◽  
Spherically Symmetric ◽  
Spherical Collapse ◽  
Radial Heat ◽  
Heat Transport Equation ◽  
Symmetric Star ◽  
Radial Heat Flux ◽  
Two Fluid

In this paper, we present an exact model of a spherically symmetric star undergoing dissipative collapse in the form of a radial heat flux. The interior of the star is matched smoothly to the generalized Vaidya line element representing a two-fluid atmosphere comprising null radiation and a string fluid. The influence of the string density on the thermal behavior of the model is investigated by employing a causal heat transport equation of Maxwell–Cattaneo form.

Study of some compact objects in R + 2βT gravity

2019 ◽  
Vol 28 (16) ◽  
pp. 2040005
Author(s):  
Arfa Waseem ◽  
M. Sharif
Keyword(s):  
Stellar System ◽  
Graphical Analysis ◽  
Compact Objects ◽  
Stellar Structure ◽  
Energy Conditions ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Star Models ◽  
Mit Bag Model ◽  
Text Model

The aim of this work is to examine the nature as well as physical characteristics of anisotropic spherically symmetric stellar candidates in the context of [Formula: see text] gravity. We assume that the fluid components such as pressure and energy density are related through MIT bag model equation-of-state in the interior of stellar system. In order to analyze the structure formation of some specific star models, the field equations are constructed using Krori–Barua solution in which the unknown constants are evaluated by employing observed values of radii and masses of the considered stars. We check the consistency of [Formula: see text] model through the graphical analysis of energy conditions as well as stability of stellar structure. It is found that our considered stars show viable as well as stable behavior for this model.

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