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We have proposed a new model of dark energy star consisting of five zones namely, solid core of constant energy density, the thin shell between core and interior, an inhomogeneous interior region with anisotropic pressures, thin shell and…

General Physics · Physics 2015-02-10 Piyali Bhar , Farook Rahaman

[Background] In our earlier work {\bf [Phys. Rev. C 104, 055804 (2021)]}, we studied the surface properties of a neutron star, assuming it as a huge finite nucleus containing protons, neutrons, electrons, and muons. For the first time, we…

Nuclear Theory · Physics 2022-04-21 Ankit Kumar , H. C. Das , Jeet Amrit Pattnaik , S. K. Patra

The observed evidence for the existence of strange stars and the concomitant observed masses and radii are used to derive an interpolation formula for the mass as a function of the radial coordinate. The resulting general mass function…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Farook Rahaman , Koushik Chakraborty , P. K. F. Kuhfittig , G. C. Shit , Mosiur Rahman

We investigate static spherically symmetric spacetimes within the framework of symmetric teleparallel $f(Q)$ gravity in order to describe relativistic stars. We adopt a specific ansatz for the background geometry corresponding to a…

General Relativity and Quantum Cosmology · Physics 2026-02-12 Nikolaos Dimakis , Alex Giacomini , Andronikos Paliathanasis , Grigorios Panotopoulos

The generic properties of compact objects made of two different fluids of dark matter are studied in a scale invariant approach. We investigate compact objects with a core-shell structure, where the two fluids are separated, and with mixed…

General Relativity and Quantum Cosmology · Physics 2023-03-01 Marie Cassing , Alexander Brisebois , Muhammad Azeem , Jürgen Schaffner-Bielich

We consider spherically symmetric spacetimes sourced by a fluid with pressure anisotropy in the radial direction. We use gauge-invariant perturbation theory to study the stability of this class of spacetimes under axial perturbations. We…

General Relativity and Quantum Cosmology · Physics 2014-07-23 Bhavesh Khamesra , V Suneeta

In this paper, stellar hydrostatic equilibrium configuration of the compact stars (neutron stars and strange stars) has been studied for $f(\mathcal{G},T)$ gravity model, with $\mathcal{G}$ and $T$ being the Gauss-Bonnet invariant and the…

General Physics · Physics 2019-11-05 M. Farasat Shamir , Mushtaq Ahmad

We investigate gravitational collapse of thick shell of fluid in the isotropic homogeneous universe without radiation described by the Einstein gravity with cosmological constant. We construct analytic solutions of this kind interpolating…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Shuichi Yokoyama

We present a class of new relativistic solutions with anisotropic fluid for compact stars in hydrostatic equilibrium. The interior space-time geometry considered here for compact objects are described by parameters namely, $\lambda$, $k$,…

General Relativity and Quantum Cosmology · Physics 2016-03-25 Bikash Chandra Paul , Rumi Deb

A new class of solutions describing the composition of compact stars has been proposed, assuming that the fluid distribution inside the star is anisotropic. This is achieved by assuming the appropriate metric potential and then solving…

General Physics · Physics 2020-03-11 D. M. Pandya , B. Thakore , R. Goti , J. P. Rank , S. Shah

We consider a spherically symmetric stellar configuration with a density profile $\rho(r)=\frac{c^2}{8\pi G r^2} $. This configuration satisfies the Schwarzchild black hole condition $\frac {2GM}{c^2 R}=~1$ for every $ r =R $. We refer it…

General Physics · Physics 2016-12-07 Mofazzal Azam , Farook Rahaman , M Sami , Jitesh R Bhatt

We study relativistic stars in the context of scalar tensor theories of gravity that try to account for the observed cosmic acceleration and satisfy the local gravity constraints via the chameleon mechanism. More specifically, we consider…

General Relativity and Quantum Cosmology · Physics 2015-03-13 E. Babichev , D. Langlois

Spherically symmetric equilibrium configurations of perfect fluid obeying a polytropic equation of state are studied in spacetimes with a repulsive cosmological constant. The configurations are specified in terms of three parameters---the…

General Relativity and Quantum Cosmology · Physics 2016-11-17 Zdeněk Stuchlík , Stanislav Hledík , Jan Novotný

Many different forms of the de Sitter metric in different coordinate systems are used in the general relativity literature. Two of them are the most common, the static form and the cosmological (exponentially expanding) form. The staticity…

General Relativity and Quantum Cosmology · Physics 2015-04-01 M. Nouri-Zonoz , J. Koohbor , H. Ramezani-Aval

We study generalizations of Buchdahl's compactness limits for perfect-fluid star solutions of $D$-dimensional Einstein gravity coupled to higher-curvature corrections. We focus on Quasi-topological theories involving infinite towers of…

General Relativity and Quantum Cosmology · Physics 2026-03-27 Pablo Bueno , Robie A. Hennigar , Ángel J. Murcia , Aitor Vicente-Cano

In the present work we study the gravitational effects of condensed dark matter on strange stars. We consider self-interacting dark matter particles with properties consistent with current observational constraints, and dark matter inside…

General Relativity and Quantum Cosmology · Physics 2017-08-02 Grigoris Panotopoulos , Ilidio Lopes

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy…

Astrophysics · Physics 2008-11-26 P. J. E. Peebles , Bharat Ratra

In this work, we explore a class of compact charged spheres that have been tested against experimental and observational constraints with some known compact stars candidates. The study is performed by considering the self-gravitating,…

General Physics · Physics 2018-08-01 Jitendra Kumar , Amit Kumar Prasad , S. K. Maurya , Ayan Banerjee

In this article, a special static spherically symmetric perfect fluid solution of Einstein's equations is provided. Though pressure and density both diverge at the origin, their ratio remains constant. The solution presented here fails to…

General Physics · Physics 2009-09-29 F. Rahaman , M. Kalam , S. Chakraborty , K. Maity , B. Raychaudhuri

In present paper a spherically symmetric stellar configuration has been analyzed by assuming the matter distribution of the stellar configuration is anisotropic in nature and compared with the realistic objects, namely, the low mass X-ray…

General Relativity and Quantum Cosmology · Physics 2021-08-26 Piyali Bhar , Tuhina Manna , Farook Rahaman , Ayan Banerjee
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