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You searched for subject:(Radiating stars ). Showing records 1 – 2 of 2 total matches.

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University of KwaZulu-Natal

1. Bogadi, Robert Sacha. Relativistic thermodynamics of radiating stars.

Degree: 2016, University of KwaZulu-Natal

In this research, on the topic of relativistic thermodynamics of radiating stars, the following three case studies are investigated: Gravitational collapse in spacially isotropic coordinates { The nature of a dissipative collapse process of a spherically symmetric star which has been perturbed into a dynamical state from an initial static con guration is studied. The collapse process involves dissipation of energy in the form of a radial heat flux. The perturbation in the density and pressure profi les are such that the star is always close to hydrostatic equilibrium. The temperature profi les are studied using a causal heat transport equation. Radiating collapse in the presence of anisotropic stresses { The effect of anisotropic stresses are investigated for a collapsing fluid sphere dissipating energy in the form of a radial flux. The collapse process starts from an initial static sphere described by the Bowers and Liang solution, and then proceeds until the time of formation of the horizon. We fi nd that the surface redshift increases as the stellar fluid moves away from isotropy. The evolution of the temperature pro les is analysed by employing a causal heat transport equation of the Maxwell-Cattaneo form. Both the Eckart and causal temperatures are enhanced by anisotropy at each interior point of the stellar con guration. The influence of an equation of state during radiative collapse { A linear equation of state is imposed on a static con guration which undergoes radiative gravitational collapse. Various values of the equation of state parameter allow descriptions of di erent matter content from classical stars to dust and also dark energy stars. The physical parameters are shown to behave in a meaningful and realistic manner. Advisors/Committee Members: Govender, M. (advisor), Maharaj, S. D. (advisor).

Subjects/Keywords: Relativistic thermodynamics.; Radiating stars.; Gravitational collapse.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bogadi, R. S. (2016). Relativistic thermodynamics of radiating stars. (Thesis). University of KwaZulu-Natal. Retrieved from http://hdl.handle.net/10413/14876

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Bogadi, Robert Sacha. “Relativistic thermodynamics of radiating stars.” 2016. Thesis, University of KwaZulu-Natal. Accessed July 15, 2019. http://hdl.handle.net/10413/14876.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Bogadi, Robert Sacha. “Relativistic thermodynamics of radiating stars.” 2016. Web. 15 Jul 2019.

Vancouver:

Bogadi RS. Relativistic thermodynamics of radiating stars. [Internet] [Thesis]. University of KwaZulu-Natal; 2016. [cited 2019 Jul 15]. Available from: http://hdl.handle.net/10413/14876.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bogadi RS. Relativistic thermodynamics of radiating stars. [Thesis]. University of KwaZulu-Natal; 2016. Available from: http://hdl.handle.net/10413/14876

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of KwaZulu-Natal

2. Brassel, Byron P. Dynamics of radiating stars in the strong gravity regime.

Degree: 2017, University of KwaZulu-Natal

We model the dynamics of a spherically symmetric radiating dynamical star, emitting outgoing null radiation, with three spacetime regions. The local internal atmosphere is a two-component system consisting of standard pressure-free, null radiation and an additional string fluid with energy density and nonzero pressure obeying all physically realistic energy conditions. The middle region is purely radiative which matches to a third region which is the Schwarzschild exterior. A large family of solutions to the field equations are presented for various realistic equations of state. A comparison of our solutions with earlier well known results is undertaken and we show that all these solutions, including those of Husain, are contained in our family. We then generalise our class of solutions to higher dimensions and consider the effects of diffusive transport We also study the gravitational collapse in the context of the cosmic censorship conjecture. We outline the general mathematical framework to study the conditions on the mass function so that future directed nonspacelike geodesics can terminate at the singularity in the past. Mass functions for several equations of state are analysed using this framework and it is shown that the collapse in each case terminates at a locally naked central singularity. These singularities are strong curvature singularities which implies that no extension of spacetime through them is possible. These results are then extended to modified gravity. We establish the result that the standard Boulware-Deser spacetime can radiate. This allows us to model the dynamics of a spherically symmetric radiating dynamical star in ve-dimensional Einstein-Gauss-Bonnet gravity with three spacetime regions. Finally, the junction conditions are derived entirely in five dimensional Einstein-Gauss-Bonnet gravity via the matching of two spacetime region leading to a model for a radiating star in higher order gravity. Advisors/Committee Members: Maharaj, Sunil D. (advisor), Goswami, Rituparno. (advisor).

Subjects/Keywords: Gravity.; Radiating stars.; Equations.; Black holes.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Brassel, B. P. (2017). Dynamics of radiating stars in the strong gravity regime. (Thesis). University of KwaZulu-Natal. Retrieved from http://hdl.handle.net/10413/15649

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Brassel, Byron P. “Dynamics of radiating stars in the strong gravity regime.” 2017. Thesis, University of KwaZulu-Natal. Accessed July 15, 2019. http://hdl.handle.net/10413/15649.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Brassel, Byron P. “Dynamics of radiating stars in the strong gravity regime.” 2017. Web. 15 Jul 2019.

Vancouver:

Brassel BP. Dynamics of radiating stars in the strong gravity regime. [Internet] [Thesis]. University of KwaZulu-Natal; 2017. [cited 2019 Jul 15]. Available from: http://hdl.handle.net/10413/15649.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Brassel BP. Dynamics of radiating stars in the strong gravity regime. [Thesis]. University of KwaZulu-Natal; 2017. Available from: http://hdl.handle.net/10413/15649

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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