Institute of Astronomy

The Scientific Quest to Explain Tabby's Star

Published on 10/10/2017 

One of the most mysterious stellar objects may be revealing some of its secrets at last.

Called KIC 8462852, also known as Boyajian’s Star, or Tabby's Star, the object has experienced unusual dips in brightness -- NASA's Kepler space telescope even observed dimming of up to 20 percent over a matter of days. In addition, the star has had much subtler but longer-term enigmatic dimming trends, with one continuing today. None of this behavior is expected for normal stars slightly more massive than the Sun. Speculations have included the idea that the star swallowed a planet that it is unstable, and a more imaginative theory involves a giant contraption or "megastructure" built by an advanced civilization, which could be harvesting energy from the star and causing its brightness to decrease.

A new study using NASA's Spitzer and Swift missions, as well as the Belgian AstroLAB IRIS observatory, suggests that the cause of the dimming over long periods is likely an uneven dust cloud moving around the star. This flies in the face of the "alien megastructure" idea and the other more exotic speculations. The smoking gun: Researchers found less dimming in the infrared light from the star than in its ultraviolet light. Any object larger than dust particles would dim all wavelengths of light equally when passing in front of Tabby's Star.

Read the NASA press release

Read more about Tabby's star on the NASA webpage

Local IoA contact: Prof Mark Wyatt (Wyatt AT ast.cam.ac.uk)

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Page last updated: 11 October 2017 at 09:10