Specular Reflections from Artificial Surfaces as Technosignature

Jaiswal, B (2023) Specular Reflections from Artificial Surfaces as Technosignature. In: Astrobiology, 23 (3). pp. 291-294.

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Abstract

Direct imaging of exoplanets will allow for observation of a planet in reflected light. Such a scenario may eventually allow for the possibility to scan a planetary surface for the presence of artificial structures made by alien civilizations. Detectability of planetary-scale structures, called megastructures, has been previously explored. In this work, we show that it is possible to detect structures of much smaller scale on exoplanetary surfaces by searching for the specular reflection of host starlight from the corresponding structures. As the planet rotates, these reflections can manifest as an optical transient riding atop the rotational light curve of the planet. Due to the directional nature of specular reflection, the reflected signal is very strong, and it is comparable to the planetary flux for surfaces that cover only a few parts per million of the total planetary surface area. By tracking the planet around its orbit, it should be possible to scan the planetary surface for any such structures that cover a size larger than a few parts per million of planetary surface. The proposed method will aid in the search for extraterrestrial intelligence in the era of direct imaging of exoplanets.

Item Type:	Journal Article
Publication:	Astrobiology
Publisher:	Mary Ann Liebert Inc.
Additional Information:	The copyright for this article belongs to Mary Ann Liebert Inc.
Keywords:	article; civilization; intelligence; surface area
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	20 Mar 2023 07:35
Last Modified:	30 Mar 2023 07:14
URI:	https://eprints.iisc.ac.in/id/eprint/81014

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