https://doi.org/10.1140/epjc/s10052-023-11486-y
Regular Article - Theoretical Physics
Observational appearance of a freely-falling star in an asymmetric thin-shell wormhole
1
Center for Theoretical Physics, College of Physics, Sichuan University, 610064, Chengdu, China
2
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, CB3 0WA, Cambridge, UK
Received:
13
February
2023
Accepted:
6
April
2023
Published online:
4
May
2023
It has been recently reported that, at late times, the total luminosity of a star freely falling in black holes decays exponentially with time, and one or two series of flashes with decreasing intensity are seen by a specific observer, depending on the number of photon spheres. In this paper, we examine observational appearances of an infalling star in a reflection-asymmetric wormhole, which has two photon spheres, one on each side of the wormhole. We find that the late-time total luminosity measured by distant observers gradually decays with time or remains roughly constant due to the absence of the event horizon. Moreover, a specific observer would detect a couple of light flashes in a bright background at late times. These observations would offer a new tool to distinguish wormholes from black holes, even those with multiple photon spheres.
© The Author(s) 2023
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