Light Ring behind Wormhole Throat: Geodesics, Images and Shadows

TL;DR

This paper investigates the geodesics, images, and shadows of the Ellis-Bronnikov wormhole, revealing unique optical features such as a light ring behind the throat and asymmetric appearances, which could be observable.

Contribution

It provides the first detailed analysis of light rings and images of asymmetric wormholes with a light ring behind the throat, highlighting potential observational signatures.

Findings

Asymmetric wormhole has one light ring and one innermost stable circular orbit on one side.

Certain light rays can be reflected back by the wormhole.

Distinct images of the wormhole with potential observational signatures.

Abstract

The geodesics of the Ellis-Bronnikov wormhole with two parameters are studied. The asymmetric wormhole has only one light ring and one innermost stable circular orbit located on one side of the wormhole throat. Consequently, certain light rays can be reflected back by the wormhole. Additionally, the same wormhole can have different appearances on both sides of the throat. We present novel images of the wormhole with a light ring behind the throat in a scenario with an accretion disk as the light source and in a backlit wormhole scenario, which are distinct from the images of other compact objects and have the potential to be observed.