Swarm of comets, not aliens, likely explains star's odd dimming

"This is a very strange star," said astronomer Massimo Marengo.

By Brooks Hays
An artistic rendering shows the glow of a star is interrupted by passing comets. Photo by NASA/JPL
An artistic rendering shows the glow of a star is interrupted by passing comets. Photo by NASA/JPL

AMES, Iowa, Nov. 24 (UPI) -- When the odd behavior of the star KIC 8462852 made the news earlier this month, many on the Internet ran with the suggestion that an alien megastructure.

Right off the bat, scientists said a swarm of comets was most likely to blame. And now new research further backs up that claim.


Initially, scientists suggested debris from a planetary collision or asteroid mashup could be to blame for the star's dimmed glow in 2011 and 2013. If that was the case, the star would be surrounded by lots of infrared light. The small bits of rock left behind by such a collision tend to radiate at infrared frequencies.

But when astronomers looked for infrared light near the star using the Spitzer Space Telescope, they found nothing.

The lack of infrared light suggests the dimming events were caused by passing comet swarms which orbit around the star -- a larger comet or group of comets in 2011 and smaller swarm in 2013.

The new study, soon to be published in the Astrophysical Journal, isn't proof of passing comets, but in ruling out other plausible scenarios makes the comet explanation one of the most likely possibilities.


Astronomers will continue to monitor the star, with hope that new observations will offer additional certainty. The ongoing mystery, scientists say, is part of the fun.

"This is a very strange star," he said. "It reminds me of when we first discovered pulsars," lead researcher Massimo Marengo, an astronomer at Iowa State University, said in a press release. "They were emitting odd signals nobody had ever seen before, and the first one discovered was named LGM-1 after 'Little Green Men.'"

As is usually the case, the odd signals revealed themselves to be a natural phenomenon.

"We may not know yet what's going on around this star," Marengo added. "But that's what makes it so interesting."

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