Shadows and precession of orbits in rotating Janis-Newman-Winicour spacetime

TL;DR

This paper constructs and analyzes the shadows and orbital precession in rotating Janis-Newman-Winicour naked singularity spacetime, revealing distinguishable features from Kerr black holes that could impact astrophysical observations.

Contribution

It introduces a method to construct rotating JNW spacetime without complexification and identifies unique shadow and precession signatures.

Findings

Rotating JNW shadows differ from Kerr black holes.

Negative orbital precession observed in JNW spacetime.

Energy conditions satisfied without complexification.

Abstract

In this paper, we construct the rotating Janis-Newman-Winicour (JNW) naked singularity spacetime using Newman-Janis Algorithm (NJA). We analyse NJA with and without complexification methods and find that the energy conditions do satisfied when we skip the complexification step. We study the shadows cast by rotating JNW naked singularity and compare them with the shadows cast by the Kerr black hole. We find that the shadow of the rotating naked singularity can be distinguished from the shadow of the Kerr black hole. While we analyse the precession of timelike bound orbits in rotating JNW spacetime, we find that it can have a negative (or opposite) precession, which is not present in the Kerr black hole case. These novel signatures of the shadow and orbital precession in rotating JNW naked singularity spacetime could be important in the context of the recent observation of the shadow of the M87 galactic center and the stellar dynamics of `S-stars' around Milkyway galactic center.