Shadow of a Naked Singularity without Photon Sphere

Understand

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 equations which has no photon sphere, and we show that the singularity casts a shadow in the absence of the photon sphere.
• We discuss some novel features of this shadow and the lightlike geodesics in this spacetime.
• We compare the shadow of the naked singularity here with shadows cast by Schwarzschild black hole and the first type of Joshi-Malafarina-Narayan (JMN1) naked singularity, where for the last two spacetimes the shadow is formed due to the presence of a photon sphere.