Reflection-asymmetric wormholes and their double shadows

TL;DR

This paper explores reflection-asymmetric wormholes connecting different Reissner-Nordstrom spacetimes, highlighting their unique observational signatures such as distinct photon rings, which could distinguish them from black holes via radioastronomy.

Contribution

It introduces a new class of reflection-asymmetric wormholes with unique observational features, expanding the understanding of possible compact objects beyond black holes.

Findings

Reflection-asymmetric wormholes can reflect a significant fraction of infalling radiation.

Their shadows may contain one or two photon rings depending on parameters.

These features can help distinguish wormholes from Kerr black holes observationally.

Abstract

We discuss construction and observational properties of wormholes obtained by connecting two Reissner-Nordstrom spacetimes with distinct mass and charge parameters. These objects are spherically symmetric, but not reflection-symmetric, as the connected spacetimes differ. The reflection-asymmetric wormholes may reflect a significant fraction of the infalling radiation back to the spacetime of its origin. We interpret this effect in a simple framework of the effective photon potential. Depending on the model parameters, image of such a wormhole seen by a distant observer (its "shadow") may contain a photon ring formed on the observer's side, photon ring formed on the other side of the wormhole, or both photon rings. These unique topological features would allow us to firmly distinguish this class of objects from Kerr black holes using radioastronomical observations.