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We study the gravitational collapse of a star with barotropic equation of state $p=w\rho$ in the context of $f({\mathcal R})$ theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory…

General Relativity and Quantum Cosmology · Physics 2015-05-28 A. H. Ziaie , K. Atazadeh , S. M. M. Rasouli

We study spherically symmetric gravitational collapse of a homogeneous perfect fluid in Rastall gravity. Considering a linear equation of state (EoS) for the fluid profiles, we examine the conditions under which the collapse scenario could…

General Relativity and Quantum Cosmology · Physics 2019-05-08 A. H. Ziaie , H. Moradpour , S. Ghaffari

This paper studies the influence of charge on a compact stellar structure also regarded as vacuum condensate star in the background of $f(\mathfrak{R},\mathcal{T}^{2})$ gravity. This object is considered the alternate of black hole whose…

General Relativity and Quantum Cosmology · Physics 2022-08-10 M. Sharif , Saba Naz

We construct a novel class of spherically symmetric and asymptotically flat black holes and naked singularities surrounded by anisotropic dark matter fluid with the equation of state (EoS) of the form $P_t=\omega \rho$. We assume that dark…

General Relativity and Quantum Cosmology · Physics 2023-02-02 Kimet Jusufi

We study the evolution of an anisotropic shear-free fluid with heat flux and kinematic self-similarity of the second kind. We found a class of solution to the Einstein field equations by assuming that the part of the tangential pressure…

General Relativity and Quantum Cosmology · Physics 2014-05-13 R. Chan , M. F. A. da Silva , C. F. C. Brandt

The gravitational collapse of a thick cylindrical shell of dust matter is investigated. It is found that a spacetime singularity forms on the symmetry axis and that it is necessarily naked, i.e., observable in principle. We propose a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ken-ichi Nakao , Yasunari Kurita , Yoshiyuki Morisawa , Tomohiro Harada

Considering gravitational collapse of Type I matter fields, we prove that, given an arbitrary $C^{2}$- mass function $\textit{M}(r,v)$ and a $C^{1}$- function $h(r,v)$ (through the corresponding $C^{1}$- metric function $\nu(t,r)$), there…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sanjay B. Sarwe , R. V. Saraykar

A naked singularity is formed by the collapse of a Sine-Gordon soliton in 1+1 dimensional dilaton gravity with a negative cosmological constant. We examine the quantum stress tensor resulting from the formation of the singularity.…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Cenalo Vaz , Louis Witten

As a preparation for the dynamical investigations, this paper begins with a short review of the three-layer gravastar model with distinguished attention to the structure of the pertinent parameter space of gravastars in equilibrium. Then…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Merse E. Gáspár , István Rácz

We propose a unique stellar model under the $f(R,\mathcal{T})$ gravity by using the conjecture of Mazur-Mottola [P. Mazur and E. Mottola, Report number: LA-UR-01-5067., P. Mazur and E. Mottola, Proc. Natl. Acad. Sci. USA 101, 9545 (2004)]…

General Relativity and Quantum Cosmology · Physics 2017-06-14 Amit Das , Shounak Ghosh , B. K. Guha , Swapan Das , Farook Rahaman , Saibal Ray

We study the gravitational vacuum star (gravastar) configuration as proposed by other authors in a model where the interior de Sitter spacetime segment is continuously extended to the exterior Schwarzschild spacetime. The multilayered…

General Relativity and Quantum Cosmology · Physics 2007-06-19 A. DeBenedictis , D. Horvat , S. Ilijic , S. Kloster , K. S. Viswanathan

This paper presents a study on gravitational vacuum stars (gravastars) with an isotropic matter distribution in de Rham-Gabadadze-Tolley (dRGT) massive gravity incorporating Buchdahl metric function. Here we have conducted an analysis on…

General Relativity and Quantum Cosmology · Physics 2025-06-16 Meghanil Sinha , S. Surendra Singh

We propose a model for an anisotropic dark energy star where we assume that the radial pressure exerted on the system due to the presence of dark energy is proportional to the isotropic perfect fluid matter density. We discuss various…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Farook Rahaman , Anil Kumar Yadav , Saibal Ray , Raju Maulick , Ranjan Sharma

Gravitational waves from compact objects provide information about their structure, probing deep into strong-gravity regions. Here we illustrate how the presence or absence of an event horizon can produce qualitative differences in the…

General Relativity and Quantum Cosmology · Physics 2010-01-07 Paolo Pani , Emanuele Berti , Vitor Cardoso , Yanbei Chen , Richard Norte

Considering the evolution of a perfect fluid with self-similarity of the second kind, we have found that an initial naked singularity can be trapped by an event horizon due to collapsing matter. The fluid moves along time-like geodesics…

General Relativity and Quantum Cosmology · Physics 2012-10-25 C. F. C. Brandt , R. Chan , M. F. A. da Silva , J. F. Villas da Rocha

We construct here a class of collapsing scalar field models with a non-zero potential, which result in a naked singularity as collapse end state. The weak energy condition is satisfied by the collapsing configuration. It is shown that…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Rituparno Goswami , Pankaj S Joshi

In this paper, we generate an exact anisotropic gravastar model using gravitational decoupling technique through minimal geometric deformation in the framework of $f(\Re, {T}^{2})$ gravity. This novel model explains an ultra-compact stellar…

General Relativity and Quantum Cosmology · Physics 2023-04-17 M. Sharif , Saba Naz

This work proposes a stellar model under Gauss-Bonnet $f(\mathcal{G}, T)$ gravity with the conjecture theorised by Mazur and Mottola, well known as the gravitational vacuum stars (gravastars). By taking into account the $f(\mathcal{G},T)$…

General Relativity and Quantum Cosmology · Physics 2018-05-24 M. Farasat Shamir , Mushtaq Ahmad

In this paper, we study the instability of naked singularities arising in the Einstein equations coupled with isothermal perfect fluid. We show that the spherically symmetric self-similar naked singularities of this system, are unstable to…

General Relativity and Quantum Cosmology · Physics 2025-05-28 Junbin Li , Xi-Ping Zhu

We study the formation of the (noncommutative) Schwarzschild black hole from collapsing shell {of the} generalized matters containing polytropic and Chaplygin gas. We show that this collapsing shell depending on various parameters forms…

General Relativity and Quantum Cosmology · Physics 2010-05-12 John J. Oh , Chanyong Park