Throat effects on shadows of Kerr-like wormholes

TL;DR

This paper studies how the throat of Kerr-like wormholes affects their shadow shapes, revealing that the throat's position can significantly alter the shadow and help distinguish wormholes from black holes.

Contribution

It introduces the effect of the wormhole throat on shadows, a factor not previously considered, providing new ways to differentiate wormholes from black holes.

Findings

Throat location can coincide with unstable photon orbits.

Throat presence significantly changes shadow shape.

Shadow features can distinguish Kerr-like wormholes from black holes.

Abstract

We revisit to investigate shadows cast by Kerr-like wormholes. The boundary of the shadow is determined by unstable circular photon orbits. We find that, in certain parameter regions, the orbit is located at the throat of the Kerr-like wormhole, which was not considered in the literature. In these cases, the existence of the throat alters the shape of the shadow significantly, and makes it possible for us to differentiate it from that of a Kerr black hole.