Scientists think “kissing” double stars will either merge or become black holes

An artist’s impression of the two stars getting intimate.
An artist’s impression of the two stars getting intimate.
Image: ESO/L. Calçada
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This is what some might call the “honeymoon period.” Things are swell between these two lovebirds now, but soon, it all ends in catastrophe.

Using their aptly-named Very Large Telescope, scientists at the European Southern Observatory have found what they’re calling “the hottest and most massive” double star ever seen. The binary system, dubbed VFTS 352, has a combined mass of roughly 60 times the size of our sun. Its surface temperatures are believed to be more than 40,000 degrees Celsius (72,000 Fahrenheit)—about 10 times hotter than the giant flaming ball of gas in our sky.

Unlike “vampire stars”—when the smaller star in a binary system sucks material away from the larger one—the stars in VFTS 352 are nearly identical in size. They orbit so close to each other that they actually overlap and share 30% of their material, in what’s called an overcontact binary system. The centers of the stars are a mere 12 million kilometers (7.5 million miles) apart—close enough to kiss, in cosmic terms.

Tarantula Nebula
A view of the Tarantula Nebula, where VFTS 352 was found.
Image: ESO/M.-R. Cioni/VISTA Magellanic Cloud survey

All good news, right? Hardly. For these star-crossed lovers, it can only end in one of two ways (pdf): Either the two stars will merge into one giant star and eventually explode in a majestic gamma-ray burst, or they’ll go supernovae when they run out of fuel and then morph into a binary black hole system—perhaps a metaphor for how their relationship was always truly dark and lifeless beneath the lovey-dovey exterior.

The astronomers say that catching an overcontact binary system in its “kissing” phase is extremely rare, because of how short it is. “The VFTS 352 is the best case yet found for a hot and massive double star that may show this kind of internal mixing,” said Leonardo A. Almeida, lead author of the study. “As such it’s a fascinating and important discovery.”

The stars are located 160,000 light years away in the Tarantula Nebula, meaning by the time we see the images, we’re observing what the stars looked like 160,000 years ago. Still, we’ll have to keep watching to find out what happens next.