Circular geodesics and accretion disks in Janis-Newman-Winicour and Gamma metric

TL;DR

This paper analyzes circular geodesics in Janis-Newman-Winicour and Gamma metrics, revealing how naked singularities influence accretion disk structures differently from black holes, with potential observational implications.

Contribution

It identifies distinct regimes of geodesic structures in these metrics and discusses their impact on accretion disk properties, extending understanding of naked singularities.

Findings

Three regimes of geodesic structures identified

Accretion disk properties differ from black holes

Potential observational signatures of naked singularities

Abstract

We study here circular timelike geodesics in the Janis-Newman-Winicour and Gamma metric spacetimes which contain a strong curvature naked singularity and reduce to the Schwarzschild metric for a specific value of one of the parameters. We show that for both the metrics the range of allowed parameters can be divided into three regimes where structure of the circular geodesics is qualitatively different. It follows that the properties of the accretion disks around such naked singularities can be significantly different from those of disks around black holes. This adds to previous studies showing that if naked singularities exist in nature, their observational signature would be significantly different from that of the black hole.