Can a naked singularity be formed during the gravitational collapse of a Janis-Newman-Winicour solution?

TL;DR

This paper investigates whether a naked singularity can form during gravitational collapse in the Janis-Newman-Winicour spacetime, concluding that cosmic censorship prevents such formation unless energy conditions are violated.

Contribution

It demonstrates that naked singularities in JNW spacetime cannot form through gravitational collapse under standard energy conditions.

Findings

Naked singularity formation is prevented during collapse under normal energy conditions.

Violating causality or null energy conditions could lead to naked singularity formation.

Weak cosmic censorship holds in the JNW spacetime during collapse.

Abstract

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 a naked singularity in the JNW spacetime, using the thin-shell approximation to describe the gravitational collapse. By introducing different matter contents to construct thin-shells, we demonstrate the impossibility of naked singularity formation during the gravitational collapse unless the causality or null energy condition of the thin-shell is violated. Therefore, the weak cosmic censorship is satisfied even with the naked singularity of the JNW spacetime.