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One of the main challenges in astronomy is the direct observation of black holes. However, differentiating them from black holes through photon observations can be difficult if Ultra-Compact Objects with unstable circular photon orbits…

General Relativity and Quantum Cosmology · Physics 2026-05-06 M. A. Anacleto , A. T. N. Silva , L. Casarini

The gravastar model, which postulates a strongly correlated thin shell of anisotropic matter surrounding a region of anti-de Sitter space, has been proposed as an alternative to black holes. We discuss constraints that present-day…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Avery E. Broderick , Ramesh Narayan

The gravastar picture is an alternative model to the concept of a black hole, where there is an effective phase transition at or near where the event horizon is expected to form, and the interior is replaced by a de Sitter condensate. In…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Francisco S. N. Lobo

We solve Einstein's equations for slowly-rotating gravitational condensate stars (gravastars) up to second order in the rotation by expanding about the spherically symmetric gravastar with de Sitter interior and Schwarzschild exterior…

General Relativity and Quantum Cosmology · Physics 2022-01-12 Philip Beltracchi , Paolo Gondolo , Emil Mottola

This paper examines the structure of a gravitationally vacuum star (also known as gravastar) in the background of ${f}(\Re,\mathcal{T}^{2})$ theory. This hypothetical object can be treated as a substitute of a black hole, with three…

General Relativity and Quantum Cosmology · Physics 2025-09-16 M. Sharif , Saba Naz

Black holes are normally and naturally associated to the end-point of gravitational collapse. Yet, alternatives have been proposed and a particularly interesting one is that of gravitational condensate stars, or gravastars. We here revisit…

General Relativity and Quantum Cosmology · Physics 2024-02-20 Daniel Jampolski , Luciano Rezzolla

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

This paper investigates the influence of charge on physical features of gravastars in the framework of energy-momentum squared gravity. A gravastar is an alternate model to a black hole that comprises of three distinct regions, namely the…

General Relativity and Quantum Cosmology · Physics 2022-04-06 M. Sharif , Saba Naz

We construct generic spherically symmetric thin-shell gravastars by using the cut-and-paste procedure. We take considerable effort to make the analysis as general and unified as practicable; investigating both the internal physics of the…

General Relativity and Quantum Cosmology · Physics 2012-08-15 Prado Martin-Moruno , Nadiezhda Montelongo Garcia , Francisco S. N. Lobo , Matt Visser

Gravastars are considered as one of the prime exotic type compact objects which may be found at the end state of gravitational collapse of massive stars with a view to resolve the complexities that are pertinent in case of a black hole…

General Relativity and Quantum Cosmology · Physics 2024-08-22 Debadri Bhattacharjee , Pradip Kumar Chattopadhyay

Viable alternatives to astrophysical black holes include hyper-compact objects without horizon, such as gravastars, boson stars, wormholes and superspinars. The authors have recently shown that typical rapidly-spinning gravastars and boson…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Vitor Cardoso , Paolo Pani , Mariano Cadoni , Marco Cavaglia

In this work we derive a gravastar model in Randall-Sundrum II braneworld scenario. Gravastars (or gravitationally vacuum stars) were proposed by Mazur and Mottola as systems of gravitational collapse alternative to black holes. The…

General Relativity and Quantum Cosmology · Physics 2019-10-08 José D V Arbañil , Pedro H R S Moraes , Manuel Malheiro

This paper investigates the gravastar model as a potential alternative to black holes, utilizing the Kuchowicz metric in the context of Rastall gravity. The model comprises three distinct regions: an interior with positive energy density…

General Relativity and Quantum Cosmology · Physics 2025-09-25 Tayyab Naseer , M. Sharif , Areej Tabassum

Within the paradigm of non-perturbative Einstein gravity we study continuous curvature manifolds which possess de Sitter interiors and Kerr exteriors. These manifolds could represent the spacetime of rotating gravastars or other similar…

General Relativity and Quantum Cosmology · Physics 2025-03-27 Sasa Ilijic , Andrew DeBenedictis

This article presents a new model-independent constraint for bouncing black hole geometries. Using the thin shell formalism, this constraint sets a bound on the minimal allowed radius of the time-like surface of the collapsing star at the…

General Relativity and Quantum Cosmology · Physics 2020-07-22 Jibril Ben Achour , Suddhasattwa Brahma , Shinji Mukohyama , Jean-Philippe Uzan

In this work, we analyze the observational properties of thin-shell gravastars under two astrophysical frameworks, namely surrounded by optically-thin accretion disks and orbited by hot-spots. We consider the thin-shell gravastar model with…

General Relativity and Quantum Cosmology · Physics 2024-04-02 João Luís Rosa , Daniela S. J. Cordeiro , Caio F. B. Macedo , Francisco S. N. Lobo

We propose a new model of a {\it gravastar} admitting conformal motion. While retaining the framework of the Mazur-Mottola model, the gravastar is assumed to be internally charged, with an exterior defined by a Reissner-Nordstr{\"o}m rather…

General Relativity and Quantum Cosmology · Physics 2011-06-06 A A Usmani , Farook Rahaman , Saibal Ray , K K Nandi , Peter K. F. Kuhfittig , Sk. A Rakib , Z Hasan

The stability of thin shell wormholes and black holes to linearized spherically symmetric perturbations about a static equilibrium is analyzed. Thin shell formalism is explored and junctions formed from combinations of Schwarzschild,…

General Relativity and Quantum Cosmology · Physics 2026-01-13 Travis Seth Rippentrop , Avijit Bera , Mustapha Ishak

In this article, we are reporting for the first time the existence of gravastar configurations in the framework of K(R,T)-gravity, which can be treated as an alternative to a black hole (Mazur and Mottola). This strengthens how much this…

General Relativity and Quantum Cosmology · Physics 2023-08-22 GRP Teruel , Ksh. Newton Singh , Tanmoy Chowdhury , Farook Rahaman , Monimala Mondal

Tidal effects related to the traversability across thin shells are examined in spherically symmetric geometries. We focus mainly on shells separating inner from outer regions of gravastars (de Sitter -- i.e. $\Lambda>0$ -- interior and…

General Relativity and Quantum Cosmology · Physics 2025-03-17 Cecilia Tomasini , Claudio Simeone , Emilio Rubín de Celis