Reflection-asymmetric wormholes and their double shadows

Abstract

We discuss construction and observational properties of wormholes obtained by connecting two Reissner-Nordstr\"om 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.