Tabby’s star

Unusual fluctuations in the luminosity of an F-type main sequence star, known as Tabby’s star (after the lead author of the initial study Tabetha Boyajian) have led to a flurry of speculation about their cause. The star’s brightness dips aperiodically by up to 20%, with the reductions lasting between 5 and 80 days. The Penn State University astronomer Jason Wright proposed that the fluctuations could be explained by an alien ‘megastructure’ and added: “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build.” Other astrophysics have since concluded that the most likely explanation for the fluctuations is that the star is surrounded by a swarm of comets or fragments of bodies too small to become planets. The orbiting objects absorb radiation, explaining the changes to luminosity.