'Alien Megastructure' Not the Cause of KIC 8462852's Dimming

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Some conspiracy theorist, however, were quick to point out that what the reseachers were seeing is an "alien megastructure" built around its star to harness its energy.

The dimming pattern of Tabby's Star was so unusual it didn't get flagged by the algorithms that sift through the data collected by NASA's planet-hunting Kepler satellite. And in May of a year ago, Boyajian got lucky: Her star began to dim.

So, while varying opinions as to what is causing the peculiar dips have been proposed over the past few years, a team of astrophysicists has now published what it believes to be the most likely answer - and it is sad news for those hopeful of extraterrestrial life being the cause.

"If a solid, opaque object like a megastructure was passing in front of the star, it would block out light equally at all colours", says Boyajian, at Louisiana State University.

The new findings come after more than 1,700 people donated over $100,000 to a Kickstarter campaign supporting further observations of the star, so compelling was the mystery surrounding it. From March 2016 to December 2017, astronomers at the Las Cumbres Observatory watched with telescopes all over the world, observing four of its weird dips.

The truth is that, even though scientists now know that Tabby's Star's mysterious behavior is not the work of aliens, they're only marginally closer to explaining the interstellar puzzle.

How do you rule out an alien megastructure, though? The star is brighter than our sun, Mike Wall reports for Space.com, but experiences some drastic dips in brightness-once even dimming up to 22 percent of its usual luminosity.

"Dust is most likely the reason why the star's light appears to dim and brighten", said Boyajian, an assistant professor of astronomy and physics at LSU. The dips in the weird star's light are nearly definitely caused by a ring of dust, not a huge opaque object between us and the star.

Dyson ring
A Dyson Ring seen in this artist's rendering was among the theories proposed to explain the dimming

KIC 8462852 is often nicknamed Tabby's star after Boyajian, who has led its observations through the roller coaster of the past couple years. There were four distinct episodes when the star's light dipped, beginning in May 2017.

Artist's concept of Tabby's Star. That instrument is created to hunt exoplanets by looking for the small dips in brightness that occur when a planet passes between its star and the telescope.

The study was published on Wednesday in the Astrophysical Journal Letters.

"We were hoping that once we finally caught a dip happening in real time we could see if the dips were the same depth at all wavelengths", Wright said in a press release. Astronomer Tabetha Boyajian and her team from Louisiana State University were combing through Kepler's data and found that the spacecraft had observed this star and recorded its unusual behavior. During the telescope's heyday, between 2009 and 2013, it stared at 150,000 stars, trying to spot these tiny changes, in the process identifying 2,341 exoplanets. "We worked very hard on clearly describing our intent to collect data to be used in testing any hypothesis". "It's going to take us a long time to get through it all".

It makes them more interesting to professional astronomers, probably.

Boyajian and her team funded the new observations via a Kickstarter campaign, which raised more than $107,000.

"We don't really have a working model quite yet, so things are still up in the air in terms of how everything is put together", Boyajian said.

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