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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.

Go deeper

Updated 42 mins ago - Politics & Policy

Inauguration Day dashboard

U.S. Capitol and stage are lit at sunrise ahead of the inauguration of Joe Biden. Photo: Patrick Semansky - Pool/Getty Images

President Trump has delivered a farewell speech and departed Washington for the last time on Air Force One, kicking off the day that will culminate with President-elect Joe Biden taking office.

What's next: The inaugural celebration for young Americans is being livestreamed, starting at 10am.

Updated 59 mins ago - Politics & Policy

Trump departs on final Air Force One flight

President Trump and his family took off on Air Force One at 9 a.m. on Wednesday morning for the final time en route to Florida.

The big picture: Trump's final hours as president were punctuated by his decisions to snub his successor's inauguration and grant pardons to many of his allies who have been swept up in corruption scandals.

Dion Rabouin, author of Markets
2 hours ago - Economy & Business

Janet Yellen said all the right things to reassure the markets

Illustration: Aïda Amer/Axios

Treasury Secretary nominee and former Fed chair Janet Yellen's confirmation hearing before the Senate Finance Committee on Tuesday showed markets just what they can expect from the administration of President-elect Joe Biden: more of what they got under President Trump — at least for now.

What it means: Investors and big companies reaped the benefits of ultralow U.S. interest rates and low taxes for most of Trump's term as well as significant increases in government spending, even before the coronavirus pandemic.

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