Read More: New Scientist
The “alien megastructure” star that has been puzzling us for the past few years might have a more ordinary explanation: an orbiting Saturn-like planet, complete with wobbling rings. In 2015, a group led by Tabetha Boyajian, then of Yale University, found that a star called KIC 8462852 had dimmed several times over a few years in a way they couldn’t explain. The star had been observed by the Kepler space telescope between 2009 and 2013 as it hunted for exoplanets by staring at a patch of sky. When a planet passes in front of a star, an event called a transit, the light intensity dips slightly and then returns to normal. But KIC 8462852, since dubbed Tabby’s star, didn’t behave that way, with the amount of dimming varying wildly. Speculation abounded, with explanations ranging from exoplanetary comets to a vast orbiting “megastructure” built by an advanced alien civilisation. Now Mario Sucerquia and his colleagues at the University of Antioquia in Colombia have proposed another possibility: a ringed planet, similar to Saturn, orbiting close to the star. Such a planet would dim the star’s light in an irregular way during a transit. First, the rings would block some of the star’s light, followed by the planet, which would dim it further. Then, after the planet passes, the rings would block some light again.