Detection Technique for Artificially-Illuminated Objects in the Outer Solar System and Beyond

TL;DR

The paper proposes a method to identify artificially-illuminated objects in the Solar System and beyond by analyzing flux variation with orbital distance, enabling detection of artificial lighting through upcoming survey data.

Contribution

It introduces a novel observational technique based on flux-distance slope analysis to distinguish artificially-illuminated objects from natural ones.

Findings

Planned surveys like LSST can measure flux variation slopes for thousands of Kuiper belt objects.

Objects with a flux slope of -2 indicate artificial illumination, unlike natural sunlight reflection.

The method can be extended to detect artificial lighting on exoplanets with future telescopes.

Abstract

Existing and planned optical telescopes and surveys can detect artificially-illuminated objects comparable in total brightness to a major terrestrial city out to the outskirts of the Solar System. Orbital parameters of Kuiper belt objects (KBOs) are routinely measured to exquisite precisions of <10^{-3}. Here we propose to measure the variation of the observed flux F from such objects as a function of their changing orbital distances D. Sunlight-illuminated objects will show a logarithmic slope alpha=(dlogF/dlog D)=-4 whereas artificially-illuminated objects should exhibit alpha=-2. Planned surveys using the proposed LSST will provide superb data that would allow measurement of alpha for thousands of KBOs. If objects with alpha=-2 are found, follow-up observations can measure their spectra to determine if they are illuminated by artificial lighting. The search can be extended beyond the Solar System with future generations of telescopes on the ground and in space, which would be capable of detecting phase modulation due to very strong artificial illumination on the night-side of planets as they orbit their parent stars.