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In this paper, we discuss some feasible features of gravastar that were firstly demonstrated by Mazur and Mottola. It is already established that gravastar associates the de-Sitter spacetime in its inner sector with the Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2020-05-05 M. Z. Bhatti , Z. Yousaf , A. Rehman

A strong gravity naked singular region can give important clues towards understanding classical as well as spontaneous nature of General Relativity. We propose here a model for energy emission from a naked singular region in a self-similar…

General Relativity and Quantum Cosmology · Physics 2018-05-23 Takafumi Kokubu , Sanjay Jhingan , Tomohiro Harada

We investigate here the locally naked singularity formed due to a spherically symmetric inhomogeneous collapsing cloud having non-zero isotropic pressure, in terms of its strength. Sufficient condition provided by Clarke and Krolak for it…

General Relativity and Quantum Cosmology · Physics 2020-03-04 Karim Mosani , Dipanjan Dey , Pankaj S. Joshi

The Janis-Newman-Winicour (JNW) spacetime possesses a naked singularity, although it represents an exact particle-like solution to the Einstein-Klein-Gordon theory with a massless scalar field. Here, we investigate the possible formation of…

General Relativity and Quantum Cosmology · Physics 2024-08-07 Xiao Yan Chew , Il Gyeong Choi , Hyuk Jung Kim , Dong-han Yeom

We investigate here the genericity and stability aspects for naked singularities and black holes that arise as the final states for a complete gravitational collapse of a spherical massive matter cloud. The form of the matter considered is…

General Relativity and Quantum Cosmology · Physics 2012-11-15 Pankaj S. Joshi , Daniele Malafarina , Ravindra V. Saraykar

There are known models of spherical gravitational collapse in which the collapse ends in a naked shell-focusing singularity for some initial data. If a massless scalar field is quantized on the classical background provided by such a star,…

General Relativity and Quantum Cosmology · Physics 2009-12-31 Tomohiro Harada , Hideo Iguchi , Ken-ichi Nakao , T. P. Singh , Takahiro Tanaka , Cenalo Vaz

We generalize here our earlier results on particle acceleration by naked singularities. We showed recently[1] that the naked singularities that form due to gravitational collapse of massive stars provide a suitable environment where…

General Relativity and Quantum Cosmology · Physics 2011-03-22 Mandar Patil , Pankaj S. Joshi , Daniele Malafarina

We present a class of exact solutions of Einstein field equations for a shear-free spherically symmetric anisotropic fluid undergoing radial heat flow. The interior metric fulfilled all the relevant physical and thermodynamic conditions and…

General Relativity and Quantum Cosmology · Physics 2016-01-21 B. C. Tewari , Kali Charan

In the current research, we present a novel gravastar model based on the Mazur-Mottola (2004) method with an isotropic matter distribution in $f(Q)$ gravity. The gravastar, a hypothesized substitute for a black hole, is built using the…

General Relativity and Quantum Cosmology · Physics 2023-04-12 Sneha Pradhan , Sanjay Mandal , P. K. Sahoo

We analyze spherical dust collapse with non-vanishing radial pressure, $\Pi$, and vanishing tangential stresses. Considering a barotropic equation of state, $\Pi=\gamma\rho$, we obtain an analytical solution in closed form---which is exact…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Sergio M. C. V. Goncalves , Sanjay Jhingan

In this paper we investigate the gravitational vacuum stars which called gravastars in the non-minimally coupled models with electromagnetic and gravitational fields. We consider two non-minimal models and find the corresponding spherically…

General Relativity and Quantum Cosmology · Physics 2021-11-18 Özcan Sert , Muzaffer Adak

We examine spherical gravitational collapse of a matter model with vanishing radial pressure and non-zero tangential pressure. It is seen analytically that the collapsing cloud either forms a black hole or disperses depending on values of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ashutosh Mahajan , Pankaj S. Joshi

We study spherically symmetric geometries made of anisotropic perfect fluid based on general relativity. The purpose of the work is to find and classify black hole solutions in closed spacetime. In a general setting, we find that a static…

General Relativity and Quantum Cosmology · Physics 2017-10-04 Hyeong-Chan Kim

In the present work, we have discussed the four dimensional spherically symmetric steller system in the framework of modified $f(T)$ gravity theory with electro-magnetic field. The field equations have been written for two cases, either…

General Relativity and Quantum Cosmology · Physics 2019-07-24 Ujjal Debnath

We explore possibility to find out a new model of gravastars in the extended $D$-dimensional Einstein-Maxwell spacetime. The class of solutions as obtained by Mazur and Mottola of a neutral gravastar \cite{Mazur2001,Mazur2004} have been…

General Physics · Physics 2017-03-02 S. Ghosh , Farook Rahaman , B. K. Guha , Saibal Ray

Any observer outside black holes cannot detect any physical signal produced by the black holes themselves, since, by definition, the black holes are not located in the causal past of the outside observer. In fact, what we regard as black…

General Relativity and Quantum Cosmology · Physics 2019-02-20 Ken-ichi Nakao , Chul-Moon Yoo , Tomohiro Harada

Gravastar models have recently been proposed as an alternative to black holes, mainly to avoid the pro\-ble\-ma\-tic issues associated with event horizons and singularities. In this work, a regular variety of gravastar models within the…

General Relativity and Quantum Cosmology · Physics 2019-03-28 Diego Julio Cirilo-Lombardo , Carlos Vigh

In this paper, we are interested to explore stable configurations of $d$-dimensional gravastars constructed from the interior $d$-dimensional de Sitter and exterior $d$-dimensional Schwarzschild/Reissner-Nordstr\"om (de Sitter) black holes…

General Relativity and Quantum Cosmology · Physics 2022-05-10 M. Sharif , Faisal Javed

In this paper, we investigate a new model of $(2+1)-$dimensional ($3D$) gravitational vacuum stars (gravastars) with an isotropic matter distribution anti-de Sitter (AdS) spacetime in the context of massive gravity. For this purpose, we…

General Relativity and Quantum Cosmology · Physics 2023-10-30 H. Barzegar , B. Eslam Panah , G. H. Bordbar , M. Bigdeli

We establish the dynamical instability of a static, spherically symmetric, and infinitesimally thin shell in general relativity. The shell is made up of a perfect fluid with a barotropic equation of state, and it produces a Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2026-04-08 Tristan Pitre , Berend Schneider , Eric Poisson