THE mystery of “alien megastructures” surrounding Tabby’s Star may finally have been solved using data from Nasa’s Spitzer and Swift missions.
For years scientists have been baffled by the unusual phenomenon of Tabby’s Star dimming and brightening.
Astronomers have previously hypothesised that the objects may repeatedly eclipse the star, also known as KIC 8462852, sparking theories of alien megastructures.
Alien hunters have argued that the phenomenon may have been caused by a Dyson swarm or sphere, a structure created by an advance civilisation which zaps light from the star.
Information from Nasa’s Spitzer and Swift missions, as well as the Belgian AstroLAB IRIS observatory, have revealed the star’s ultraviolet light is dimming more than its infrared.
And according to experts, this means something much smaller than the proposed Dyson Sphere has caused the mysterious phenomenon.
In the new study published in the Astrophysical Journal, researchers have proposed space dust may be to blame.
Huan Meng, lead author of the study at the University of Arizona, Tucson 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.”
The researchers collected observational data of Tabby's star from October 2015 to March 2017 from two Nasa telescopes – Swift, which takes X-ray and UV measurements, and Spitzer, which measures objects in infrared.
Dr Meng said: “We found that from UV, throughout the visible spectrum, to IR, the star is dimming at every wavelength we monitored.”
The researchers discovered that the dimming rate of Tabby's star differed significantly between UV and infrared, suggesting “micro-sized dust screens”.
While scientists suspect the dimming is caused by a dust ring, they stress that “this is not a firm conclusion”.
Dr Meng said: “It cannot be anything from the interstellar medium.
“Only microscopic fine-dust screens are able to scatter the starlight in the way characterised by measurements.”
Tabby’s Star, which located 1,400 light years away dims at a much faster rate than other stars and has baffled astronomers since it was first discovered in 2015.