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Cambridge University Science Magazine

NASA’s Kepler space telescope was launched in March 2009 with the goal of discovering Earth-like exoplanets. It also may have found something altogether more surprising. Citizen scientists of the Planet Hunters project, who are involved in visually analyzing the Kepler data, flagged up the star KIC 8462852. Extraordinarily, the recorded light emission curves of the star show irregular and quite variable dips in brightness. These dips do not look anything like the faint periodic dimming of a star that is seen when an orbiting planet passes in front of it.

A team of astronomers led by Dr. Tabetha S. Boyajian at Yale University recently published a paper characterizing KIC 8462852 and discussing possible causes for the puzzling observations. The researchers ruled out errors in the recording equipment or computational artifacts as well as intrinsic variability or influence of neighbouring stars as explanations. They reviewed several theories involving dust clouds or collisions in the star system and judged them to be unlikely. The scenario they favoured involves passing fragments of a broken-up comet on a highly eccentric orbit. They noted that though it is not a perfect fit for the data, it is the most likely natural explanation.

Intriguingly, the data gathered about KIC 8462852 was discussed in another paper by a group of astronomers from the University of Pennsylvania. They hypothesized about transiting megastructures built by technologically advanced civilizations, for example for the purpose of gathering solar energy. The group asserted that instead of a formation of asteroid fragments passing the star, the cause for the aperiodic dimming could be such a swarm of megastructures.

The SETI Institute is currently investigating KIC 8462852 via its Allen Telescope Array in search of artificial radio waves. Scientists are quite sober about the chances of finding proof of alien intelligence near the star, but they do think it warrants further investigation.

DOI: arXiv:1510.04606, DOI: arXiv:1509.03622

Written by Janina Ander.