‘Alien Megastructure’ Ruled Out for Star’s unusual dimming

Artist’s illustration depicting a hypothetical dust ring orbiting KIC 8462852, also known as Tabby’s Star.
Credit: NASA/JPL-Caltech

A new study suggests that dimming of “Tabby’s star”, or more formally, KIC 8462852, is not caused by an alien megastructure being currently built. Instead it is very likely caused by dust orbiting the star. Astronomers discovered that the dimming was more pronounced in UV wavelengths than infrared. The members of the study team proceeded to say that objects larger than a dust grain would cause a consistent dip in across all wavelengths. Lead author Huan Meng said “This pretty much rules out the alien megastructure theory, as that could not explain the wavelength-dependent dimming,”

“We suspect, instead, there is a cloud of dust orbiting the star with a roughly 700-day orbital period.”

 
Strange dimming

KIC 8462852 is an F-type main-sequence star located in the constellation Cygnus approximately 1,280 light-years from Earth. The star gained it’s more widely known name is 2015, where it’s unusual dimming events got discovered. Over the past half-decade, the star’s dipped by 22%. When you consider that  the transit of a Jupter-sized star would block a mere 1% of the light, demonstrates just how massive a drop of 22% is. Since the discovery, many speculations have been made about the origin of the dimming, from an advanced alien race constructing the hypothetical dyson sphere to swarms of comets and fragments of planets.

The observed Ultraviolet dip implicates circumstellar dust; grains large enough to stay in orbit around Tabby’s star despite the radiation pressure but small enough that they don’t block light uniformly in all wavelengths, the researchers said. 

However, mysteries still remain as another study led by Joshua Simon just discovered the star experienced two brightening spells over the past 11 years. The observed UV dip implicates circumstellar dust — grains large enough to stay in orbit around Tabby’s star despite the radiation pressure but small enough that they don’t block light uniformly in all wavelengths, the researchers said. The study can be read here for free

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