Biggest Yellow “Hypergiant” Star Spotted

A yellow hypergiant star.
HR 5171, the brightest star just below the center in this wide-field image, is a yellow hypergiant, a very rare type of star.
Credit: ESO/Digitized Sky Survey 2

A jumbo star 1,300 times wider than the sun has surprised astronomers, who report it is the biggest yellow “hypergiant” star ever spotted. Dubbed HR 5171, the star is also surprising because a companion star was discovered orbiting it.

“The two stars are so close that they touch, and the whole system resembles a gigantic peanut,” says lead astronomer Olivier Chesneau of France’s Observatoire de la Côte d’Azur, in a statement.

Only about a dozen of these yellow hypergiants are known, according to ESO, the European Southern Observatory. HR 5171 ranks among the top ten widest stars known, belonging to a class of giant stars that cool and swell as they age.

It is about 12,000 light-years away and is visible to the naked eye in the nighttime sky, residing in the constellation of Centaurus, the Centaur.

Yellow hypergiant star HR 5171
An artist’s impression shows the yellow hypergiant star HR 5171. Credit: ESO



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