Remember KIC 8462852, that odd little star that was observed inexplicably dipping in brightness and which people though might have been some sort of advanced alien megastructure? Scientists may be sure advanced extraterrestrial civilizations aren’t responsible, but what is?!
According to new research posted last week to the arXiv server, researchers still aren’t sure. The star’s output has been seen dipping by as much as one-fifth—which is too much to be caused by a transiting planet—and now Bradley Schaefer of Louisiana State University has crossed comets off the list of possible explanations after an in-depth review of historical observations.
The comet explanation, proposed in September by Yale University’s Tabetha Boyajian and her colleagues, said that dust from a large cloud of comets was the likely cause of the star’s changes in brightness. Now, Schaefer reviewed photographic plates of the sky dating back to the late 19th century and found that, over the past century, KIC 8462852’s light output has steadily faded by about 19 percent, according to Gizmodo and New Scientist.
That’s “completely unprecedented for any F-type main sequence star,” Schaefer said. Boyajian added that the new study “presents some trouble for the comet hypothesis,” telling New Scientist that they “need more data through continuous monitoring to figure out what is going on.”
Flickering would have required too many comets, study finds
Previously, a study published by Jason Wright of Penn State University and his colleagues said that it was possible that “alien megastructures,” such as satellites developed to gather light from the star, could potentially have been the cause of the unusual signal. However, the ensuing search for evidence in the form of radio signals or laser beams came up empty.
While Schafer is not convinced that comets are the cause of the phenomenon, he also does not believe Wright’s alien megastructure hypothesis, which he told New Scientist “runs wrong with my new observations.” Not even the most advanced extraterrestrial civilization would be able to create something capable of covering that much of a star in just 100 years, he said, and an object that light should be radiating light absorbed from the star as heat. KIC 8462852’s does not.
“I don’t know how the dimming affects the megastructure hypothesis, except that it would seem to exclude a lot of natural explanations, including comets,” Wright said. “It could be that there were just more dimming events in the past, or that astronomers were less lucky in the past and caught more dimming events in the 1980s than in the 1900s. But that seems unlikely.”
Schaefer’s findings saw that the dimming effect observed around the star would have needed nearly 650,000 comets, each nearly 125 miles (200 kilometers) wide, to have passed by the star. That, he said, is extremely implausible, and his research is “refutation of [that] idea, and indeed, of all published ideas.”
So the mystery of KIC 8462852 deepens. Scientists are convinced that aliens, comets, and transiting planets aren’t to blame for its flickering behavior, but what is? It may be some time before researchers can provide an answer to that question.
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Feature Image: NASA/JPL-Caltech
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