A Search for Optical Laser Emission from Proxima Centauri

TL;DR

This study conducted a comprehensive search for optical laser signals from Proxima Centauri over 15 years, finding no evidence of extraterrestrial technological emissions despite detecting some instrumental artifacts.

Contribution

The paper presents the first extensive optical laser search from Proxima Centauri, including analysis of 107 spectra, and clarifies the origin of spectral combs as instrumental, not extraterrestrial.

Findings

No evidence of laser signals from Proxima Centauri was found.

Spectral combs detected are of instrumental origin, not technological.

The search rules out laser emissions above 20-120 kW within the observed field.

Abstract

A search for laser light from Proxima Centauri was performed, including 107 high-resolution, optical spectra obtained between 2004 and 2019. Among them, 57 spectra contain multiple, confined spectral combs, each consisting of 10 closely-spaced frequencies of light. The spectral combs, as entities, are themselves equally spaced with a frequency separation of 5800 GHz, rendering them unambiguously technological in origin. However, the combs do not originate at Proxima Centauri. Otherwise, the 107 spectra of Proxima Centauri show no evidence of technological signals, including 29 observations between March and July 2019 when the candidate technological radio signal, BLC1, was captured by Breakthrough Listen. This search would have revealed lasers pointed toward Earth having a power of 20 to 120 kilowatts and located within the 1.3au field of view centered on Proxima Centauri, assuming a benchmark laser launcher having a 10-meter aperture.