Radiating collapse in the presence of anisotropic stresses

Govender, M.; Bogadi, Robert S.; Lortan, Darren; Maharaj, S. D.

doi:10.1142/s0218271816500371

Cited by 15 publications

(15 citation statements)

References 19 publications

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“…This scenario has been studied by several authors yielding rich insights into the collapse process [12][13][14][19][20][21]. The interior spacetime of our radiating stellar model is described by a spherically symmetric shear-free line element in simultaneously comoving and isotropic coordinates.…”

Section: Interior Spacetimementioning

confidence: 99%

“…In order to find exact solutions of the field equations describing dissipative collapse, various assumptions on the gravitational potentials and matter content of the gravitating body were made. These included acceleration-free collapse, Weylfree collapse, expansion-free collapse, anisotropic pressure profiles, inclusion of bulk viscosity and an equation of state [18][19][20][21]. The Santos junction conditions leads to a differential equation governing the temporal behaviour of the model.…”

Section: Introductionmentioning

confidence: 99%

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Radiating star with a time-dependent Karmarkar condition

Naidu

Govender

2018

Eur. Phys. J. C

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In this paper we employ the Karmarkar condition (Proc Indian Acad Sci A 27:56, 1948) to model a spherically symmetric radiating star undergoing dissipative gravitational collapse in the form of a radial heat flux. A particular solution of the boundary condition renders the Karmarkar condition independent of time which allows us to fully specify the spatial behaviour of the gravitational potentials. The interior solution is smoothly matched to Vaidya's outgoing solution across a time-like hypersurface which yields the temporal behaviour of the model. Physical analysis of the matter and thermodynamical variables show that the model is wellbehaved.

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Section: Interior Spacetimementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Radiating star with a time-dependent Karmarkar condition

Naidu

Govender

2018

Eur. Phys. J. C

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“…It is well-known that pressure anisotropy plays an important role during dissipative collapse. In a recent study by Govender et al [48] it has been shown that the dynamics of a collapsing core is closely related to the radial pressure and energy density of the stellar fluid. By assuming a linear equation of state for the initial static configuration of the form p r = αρ − β where α and β are constants, they demonstrated that the subsequent collapse is sensitive to the interplay between the radial pressure and energy density.…”

Section: Generating a New Family Of Embedding Class I Modelsmentioning

confidence: 99%

“…Using the boundary condition (47)(48)(49), we get (50-52). The gravitational red-shift of the stellar system is given by…”

Section: Matching Of Physical Boundary Conditionsmentioning

confidence: 99%

“…A natural question that arises from these investigations is how the initial static configuration (the state of the stellar fluid just before the onset of collapse) affects the outcome of gravitational collapse. To this end there have been various approaches in modeling dissipative collapse starting from an initial static configuration [10][11][12]. It has been shown that pressure anisotropy, shear, inclusion of charge, dimensionality of spacetime and equation of state of the initially static core affects the subsequent collapse.…”

Section: Introductionmentioning

confidence: 99%

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Physical viability of fluid spheres satisfying the Karmarkar condition

2017

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We obtain a new static model of the TOV-equation for an anisotropic fluid distribution by imposing the Karmarkar condition. In order to close the system of equations we postulate an interesting form for the g rr gravitational potential which allows us to solve for g tt metric component via the Karmarkar condition. We demonstrate that the new interior solution has well-behaved physical attributes and can be utilized to model relativistic static fluid spheres. By using observational data sets for the radii and masses for compact stars such as 4U 1538-52, LMC X-4 and PSR J1614-2230 we show that our solution describes these objects to a very good degree of accuracy. The physical plausibility of the solution depends on a parameter c for a particular star. For 4U 1538-52, LMC X-4 and PSR J1614-2230 the solutions are well-behaves for 0.1574 ≤ c ≤ 0.46, 0.1235 ≤ c ≤ 0.35 and 0.05 ≤ c ≤ 0.13 respectively. The behavior of the thermodynamical and physical variables of these compact objects lead us to conclude that the parameter c plays an important role in determining the equation of state of the stellar material and observed that smaller values of c lead to stiffer equation of states.

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Complexity‐Free Anisotropic Solution of Buchdahl's Model and Energy Exchange Between Relativistic Fluids by Extended Gravitational Decoupling

Maurya

Singh

Govender

et al. 2023

Fortschritte der Physik

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In this work, we present an anisotropic generalization of the Buchdahl static stellar model by implementing the method of extended gravitational decoupling and further requirement of vanishing complexity (Herrera, Phys Rev D 97:044010,2018). Starting off with a general spherically symmetric static metric with two unknown gravitational potentials, we impose the condition of vanishing complexity which then reduces the problem to a single-generating metric function [Contreras and Stuchlik, Eur. Phys. J. C (2022) 82:706]. The Buchdahl ansatz is then employed to obtain the complete gravitational behavior of the isotropic seed solution. The method of extended gravitational decoupling is thereafter utilized to obtain an anisotropic counterpart of the Buchdahl perfect gravitating sphere. We subject our solution to rigorous physical tests to ensure that it serves as a viable candidate for compact objects such as neutron stars as well as pulsars. We show that the decoupling parameter plays a crucial role in determining the stability and regularity of several key physical features of the entire stellar model. A novel finding of our investigation is the energy exchange between the seed solution and the secondary source which we show is sensitive to the decoupling parameter. In addition, it has also been shown that the direction of energy flow depends on the radial distance of the shell from the center of the stellar configuration.

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Radiating collapse in the presence of anisotropic stresses

Cited by 15 publications

References 19 publications

Radiating star with a time-dependent Karmarkar condition

Radiating star with a time-dependent Karmarkar condition

Physical viability of fluid spheres satisfying the Karmarkar condition

Complexity‐Free Anisotropic Solution of Buchdahl's Model and Energy Exchange Between Relativistic Fluids by Extended Gravitational Decoupling

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