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The Janis-Newman-Winicour (JNW) spacetime can describe a naked singularity with a photon sphere that smoothly transforms into a Schwarzschild black hole. Our analysis reveals that photons, upon entering the photon sphere, converge to the…

General Relativity and Quantum Cosmology · Physics 2023-09-20 Deyou Chen , Yiqian Chen , Peng Wang , Tianshu Wu , Houwen Wu

In the present paper we study the geodesic structure of the Janis-Newman-Winicour(JNW) space-time which contains a strong curvature naked singularity. This metric is an extension of the Schwarzschild geometry when a massless scalar field is…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Sheng Zhou , Ruanjing Zhang , Juhua Chen , Yongjiu Wang

This paper explores the unique observational signatures of accretion onto a Janis-Newman-Winicour (JNW) strongly naked singularity, particularly in the absence of a photon sphere. The surrounding spacetime of such a singularity exhibits…

General Relativity and Quantum Cosmology · Physics 2025-05-20 Zeqian Zhang

We extend the method of Simpson and Visser (SV) of regularising a black hole spacetime, to cases where the initial metric represents a globally naked singularity. We choose two particular geometries, the Janis-Newman-Winicour (JNW) metric…

General Relativity and Quantum Cosmology · Physics 2023-05-31 Kunal Pal , Kuntal Pal , Pratim Roy , Tapobrata Sarkar

We construct a generalized class of Joshi-Malafarina-Narayan (JMN) naked singularity spacetimes that arise as equilibrium end states of gravitational collapse with non-vanishing tangential pressure. The generalization introduces density…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Jay Verma Trivedi , Pankaj S. Joshi

Though the cosmic censorship conjecture states that spacetime singularities must be hidden from an asymptotic observer by an event horizon, naked singularities can form as the end product of a gravitational collapse under suitable initial…

General Relativity and Quantum Cosmology · Physics 2020-12-24 Avijit Chowdhury , Narayan Banerjee

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

The motion of time-like test particles in the Fisher/Janis-Newman-Winicour (F/JNW) spacetime is studied with the Hamiltonian formulation of the geodesic equations. The spacetime is characterised by its mass parameter $r_g$ and scalar field…

General Relativity and Quantum Cosmology · Physics 2017-10-27 Gulmina Zaman Babar , Adil Zaman Babar , Yen-Kheng Lim

Janis-Newman-Winicour (JNW) spacetimes generalize the Schwarzschild solution to include a massless scalar field. Although suffering from naked singularities, they share the `frozen star' features of Schwarzschild black holes. Cosmological…

High Energy Physics - Theory · Physics 2017-01-18 David Kastor , Jennie Traschen

The study investigates orbital motion of test particles near compact objects described by solutions involving massless scalar fields, electromagnetic fields, and nonlinear electrodynamics. Specifically, we analyze orbital dynamics in the…

General Relativity and Quantum Cosmology · Physics 2025-08-29 J. Horák , T. Tahamtan , T. Hale , G. Török , A. Kotrlová , E. Šrámková

It is now theoretically well established that not only a black hole can cast shadow, but other compact objects such as naked singularities, gravastar or boson stars can also cast shadows. An intriguing fact that has emerged is that the…

General Relativity and Quantum Cosmology · Physics 2021-06-25 Kanwar Preet Kaur , Pankaj S. Joshi , Dipanjan Dey , Ashok B. Joshi , Rucha P. Desai

It is generally believed that the shadows of either a black hole or naked singularity arise due to photon spheres developing in these spacetimes. Here we propose a new spherically symmetric naked singularity spacetime solution of Einstein…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Ashok B. Joshi , Dipanjan Dey , Pankaj S. Joshi , Parth Bambhaniya

We derive here the orbit equations of particles in naked singularity spacetimes, namely the Bertrand (BST) and Janis-Newman-Winicour (JNW) geometries, and for the Schwarzschild black hole. We plot the orbit equations and find the Perihelion…

General Relativity and Quantum Cosmology · Physics 2019-09-23 Ashok B. Joshi , Parth Bambhaniya , Dipanjan Dey , Pankaj S. Joshi

We investigate whether a timelike naked singularity of negative-mass Schwarzschild type can be causally dressed by a static anisotropic matter distribution in classical general relativity. Working within a spherically symmetric framework,…

General Relativity and Quantum Cosmology · Physics 2026-05-19 Pablo León , G. Alencar , Manuel Gonzalez-Espinoza , Francisco Tello-Ortiz

The final fate of gravitational collapse of massive stars has been a subject of interest for a long time since such a collapse may lead to black holes and naked singularities alike. Since, the formation of naked singularities is forbidden…

General Relativity and Quantum Cosmology · Physics 2020-09-16 Subhadip Sau , Indrani Banerjee , Soumitra SenGupta

A hairy extension of the Bertotti-Robinson regular spacetime has been recently introduced in the context of the Einstein-Maxwell-Scaler theory that surprisingly is a singular black hole formed in the $S_{3}$ background spatial topology…

General Relativity and Quantum Cosmology · Physics 2023-07-06 Vahideh Memari , S. Habib Mazharimousavi

We investigate the timelike geodesics and the periapsis precession of orbits in the Fisher-Janis-Newman-Winicour-Wyman spacetime. This spacetime represents the naked singularity spacetime in the Einstein-massless scalar system. We revisit…

General Relativity and Quantum Cosmology · Physics 2022-01-26 Keisuke Ota , Shinpei Kobayashi , Keisuke Nakashi

The general theory of relativity predicts the relativistic effect in the orbital motions of S-stars which are orbiting around our Milky-way galactic center. The post-Newtonian or higher-order approximated Schwarzschild black hole models…

General Relativity and Quantum Cosmology · Physics 2022-10-04 Parth Bambhaniya , Ashok B. Joshi , Dipanjan Dey , Pankaj S. Joshi , Arindam Mazumdar , Tomohiro Harada , Ken-ichi Nakao

In this paper, we investigate the light trajectories and shadow properties in the rotating version of null naked singularity (NNS) spacetime which is derived using the Newman- Janis algorithm without complexification method. We discuss some…

General Relativity and Quantum Cosmology · Physics 2022-09-21 Vishva Patel , Divya Tahelyani , Ashok B. Joshi , Dipanjan Dey , Pankaj S. Joshi

We formulate a generic Newtonian like analogous potential for static spherically symmetric general relativistic (GR) spacetime, and subsequently derived proper Newtonian like analogous potential corresponding to Janis-Newman-Winicour (JNW)…

General Relativity and Quantum Cosmology · Physics 2015-11-09 Shubhrangshu Ghosh , Tamal Sarkar , Arunava Bhadra
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