Mysterious 'alien megastructure' star might finally have an explanation

Saturday, 13 Jan, 2018

Boyajian "absolutely" intends to pursue follow-up observations of KIC 8462852, but she isn't sure whether numerous same contributors to the first Kickstarter campaign would come back in light of the fact that aliens have been ruled out. The cloud was most possibly produced by the collision of two comets or the break-up of a single one. Maybe. Boyajian's challenge will be to market that investigation in a way that replicates the excitement of alien megastructures.

'Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure'. These funds were used to support a dedicated, ground-based telescopic survey of Tabby's Star at the Las Cumbres Observatory in Goleta, California, which worked in tandem along with a network of professional and amateur telescopes around the world.

Astronomers even pointed one of the planet's most sensitive radio telescopes at the star, hoping to hear murmurs from a civilization intelligent enough to craft structures so large they sometimes block a substantial portion of the star's light.

Instead, the star, which is about 50 percent larger than the sun, 1,000 degrees hotter and 1,000 light-years away, was seen dimming a lot more at some wavelengths than at others, leading the researchers to conclude light from the star was being obscured by dust, which is not opaque.

For the past few years, astronomers have been scratching their heads while trying to figure out the reason for the drastic dimming of Tabby's star. The star is now middle-aged which means the production of so much dust is just not possible. After the four dips (collectively known as Elsie, which is derived from the "LC" of Las Cumbres Observatory, the most generous Kickstarter backer), the star exhibited odd and unexpected brightening for a couple of months.

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

Wright said the mention of aliens attracts interest from many areas, be it the general public or scientists searching for extraterrestrial life. That's not what the team saw.

Boyajian noted that if something like a planet were blocking the light, it would block all wavelengths by the same amount. Since blue light has much shorter wavelengths than red light, it's much more easily blocked by smaller materials, such as fine grains like dust. This is why our sky is blue; that colour has been scattered out of the sun's direct light by the molecules in the air.

Tabby's Star, a mysterious dimming star that has puzzled astronomers so completely that the wildest of explanations for its behavior have been proposed, turns out to be a natural astronomical phenomenon after all. They paid over $100,000 for the privilege to study the star in closer detail and their observations were published in Astrophysical Journal Letters this week. Suggestions ranged from the usual suspects, exoplanets and comets, to the possibility that Tabby's Star was host to a megastructure built by aliens to capture the star's energy output. It reinforces the conclusions reached by Huan Meng, University of Arizona, Tucson, and collaborators in October 2017.

While it is not aliens this time, the story serves as a valuable reminder that unexpected signals of this kind are definitely the ones to look out for.

Not only that, but many observations were also conducted by amateur astronomers.

Stuart Clark is the author of The Search for Earth's Twin (Quercus).