Charged anisotropic spherical collapse with heat flow

Abstract

In this article, we study the shear-free gravitational collapse of a charged radiating star. The Einstein field equations of gravitational collapse for the charged stars are known to give rise to a high degree of non-linearity in the ordinary differential equation coming from junction conditions. The attempts to solve it analytically proved to be unfortunate. Numerical methods have been suggested in the past. However, the high degree of non-linearity tends to introduce fluctuations and large round off errors in the numerical calculation. A new ansatz is proposed in the present work to reduce the degree of non-linearity. An ordinary differential equation is derived by satisfying junction conditions, and its numerical solution is demonstrated. Physical quantities associated with the collapse process are plotted to observe the effect of charge on these quantities. It is concluded that the charge can delay the collapse of a star and can even prevent it depending upon the amount of charge. It is also verified that the solution satisfies all the energy conditions.

Inhomogeneous and Radiating Composite Fluids

“…Making use of (30) and the solutions (75), ( 76) and (79), the dominant energy conditions can be expressed as:…”

“…They have also been used in the description of static compact spheres in Einstein-Gauss-Bonnet gravity; some examples are contained in the works [25][26][27]. The energy conditions have been applied in the modeling of radiating stars, which are heat-conducting and undergoing dissipation [28][29][30]. It is important to point out that the energy conditions for a Type I imperfect fluid that conducts heat and radiates energy were first considered by Kolassis et al [31].…”

Radiating composite stars with electromagnetic fields

“…A geodesic stellar body in the presence of a e-mail: maharaj@ukzn.ac.za (corresponding author) b e-mail: drbrasselint@gmail.com the electromagnetic field was generated by Ivanov [12] and Mahomed et al [13]. Also, the condition for vanishing shear was made by Charan et al [14], and the shear-free condition has been investigated in different physical scenarios [15][16][17]. Particular models are known which have nonzero shear [18][19][20][21].…”

First Integrals of Shear-Free Fluids and Complexity

“…where the integral can be expressed in terms of elementary functions depending on the sign of A − BC. For this case, it is not possible to obtain the function u(x) explicitly, as it is not possible to evaluate the integral on the right hand side of (26). Therefore the solution can only be given parametrically.…”

“…Some particular exact models have been found using this framework [22][23][24][25]. The special case of vanishing shear provides new insights into the behaviour of gravity, and some particular radiating stellar models have been generated [26][27][28][29]. Our approach in this paper is to find a general result, namely a first integral, in a shear-free fluid without having to specify the gravitational potentials.…”