Search

This paper deals with the study of quasi-spherical gravitational collapse in the framework of f (R , T) theory. We will divide geometry of the star into two distinct portions i.e. interior portion and exterior portion. In the interior portion, we consider quasi-spherical Szekeres line element and in the exterior portion we take Vaidya line element. The interior and exterior portions will be glued by using Israel's junction conditions [W. Israel, Il Nuovo Cimento B (1965–1970) 44, 1 (1966); W. Israel, Phys. Lett. A 24, 184 (1967)]. The field equations will be derived in the context of f (R , T) theory for a particular model. Apparent horizons and their time configuration for various desirable cases will also be discussed. [ABSTRACT FROM AUTHOR]

This paper examines the structure of a gravitational vacuum star (also known as gravastar) in the background of f (ℜ , 2) theory. This hypothetical object can be treated as a substitute of a black hole, with three regions: (i) the internal region, (ii) the intrinsic shell and (iii) the outer region. We examine these geometries using Finch–Skea metric for the radial metric component along with the particular f (ℜ , 2) model. We determine singularity-free solutions for both the inner as well as thin-shell domains. The smooth matching of the interior region with external Schwarzschild spacetime is obtained through Israel matching constraints. Finally, we study various characteristics of gravastar domains including the equation-of-state parameter, proper length, entropy, energy as well as surface redshift. It is found that the compact gravastar structure is a viable alternate to the black hole in the perspective of this gravity. [ABSTRACT FROM AUTHOR]

This paper examines the structure of gravastar (gravitationally vacuum star) in the background of f (ℜ , 2) theory. The gravastar can be regarded as a substitute for a black hole comprising of three regions (i) the interior domain, (ii) the intrinsic shell and (iii) the exterior domain. We investigate these domains by employing Karmarkar's condition by assuming a specific f (ℜ , 2) model. The field equations are solved to evaluate nonsingular solutions of both the interior and intermediate regions. Inner as well as outer spacetimes are matched together using Israel formalism to obtain density and pressure at the joining surface. Different attributes of gravastar like the equation of state parameter, proper length, entropy and energy are analyzed through graphical behavior. It is found that the gravastar model is a viable alternative to the black hole in the context of this gravity. [ABSTRACT FROM AUTHOR]

This paper is devoted to studying the structure of gravitationally vacuum condensate stars under the influence of matter and geometry coupled gravity. This alternative to black hole comprises three domains, i.e. interior, exterior and thin-shell. We investigate such regions by considering particular equations of state for a specific model of energy–momentum squared gravity. The nonsingular solutions of field equations are obtained to describe the interior region of gravastar and the Schwarzschild spacetime represents the exterior region. The junction conditions are used to match interior and exterior domains while Lanczos equations provide the surface density and pressure at thin-shell. We investigate various attributes of gravastar such as the equation of state parameter, entropy, proper length as well as energy. The physical features of a gravitationally vacuum star indicate a linear relationship with the thickness of the shell and provide a viable structure similar to general relativity. [ABSTRACT FROM AUTHOR]