For years, scientists have been baffled by KIC 8462852—otherwise known as Tabby’s star. The star has captured the imaginations of many, with alien enthusiasts arguing the star is home to an alien megastructure. Now, a new study has just proposed that the unusual fading of the star is probably caused by clouds of dust.
Huan Meng of the University of Arizona believes that the dimming is caused by a cloud of fine dust particles. The conclusion was reached after observing the star with the infrared Spitzer and ultraviolet Swift space telescopes from October 2015 to December 2016. Their studies mark the first observations of the star in multiple wavelengths of light, revealing that the star is dimming faster in short blue wavelengths than longer infrared ones.
“That almost absolutely ruled out the alien megastructure scenario, unless it’s an alien microstructure,” Meng says.
Tabby’s star is famous for dropping in brightness by up to 22 percent over the course of a few days and fading by about 4 percent by year. Before Meng’s observations, Joshua Simon of the Observatories of the Carnegie Institution for Science found a similar dimming and identified a moment in 2014 when the star grew brighter.
“That’s fascinating,” says astrophysicist Tabetha Boyajian of Louisiana State University in Baton Rouge. “We always speculated that it would brighten sometime. It can’t just get fainter all the time — otherwise, it would disappear. This shows that it does brighten.”
Simon argued that the brightening could be due to a magnetic cycle like the sun’s, but no known cycle makes a star brighten quite so much.
“This adds some intrigue to what’s going on, but I don’t think it really changes the landscape,” says Brian Metzger, who was not involved in the new studies.