This illustration depicts dust orbiting Tabby's Star. Illustration: NASA/JPL-Caltech

Several theories surround what is known as the "most mysterious star in the universe" — one in the Milky Way that is slightly bigger than our Sun and whose sporadic dimming and brightening puzzles scientists.

New data, published Wednesday in The Astrophysical Journal Letters, suggests the flickering is likely caused by a cloud of small dust particles — and not an alien megastructure orbiting the star, as some researchers hypothesized.

Their methodology: The scientists observed "Tabby's Star," nicknamed after Louisiana State University astronomer Tabetha Boyajian who led the study, through the Las Cumbres Observatory from March 2016 to December 2017, during which the star's light dipped four times.

Their findings, detailed in The Atlantic: The dimming they observed was much deeper at blue wavelengths than at red wavelengths, meaning that the object blocking the star was not opaque (an opaque object would block both colors in equal measure). That discovery led Boyajian's team to the conclusion that cosmic dust particles "just big enough to stick inside the star's orbit, but too small to block light in all wavelengths" are responsible.

Key quote: "Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure," Boyajian told The Atlantic.

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