Stars locked in potentially fatal cosmic "kiss"

It's a potentially dangerous "kiss."

Thanks to the European Southern Observatory's (ESO) Very Large Telescope, astronomers discovered the largest and hottest double star. Located in the Tarantula Nebula -- about 160,000 light-years from Earth -- the two astral bodies making up the VFTS 352 star system nearly touch one another, which means that they could either create one giant star or create a binary black hole.

"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 study lead author Leonardo A. Almeida, of the University of Sao Paulo, Brazil, in a press release. "As such it's a fascinating and important discovery."

There is a distance of just about 7.4 million miles separating the centers of the stars, and their surfaces are so close that a bridge formed between them. Collectively, the stars are huge. They possess a combined mass that is about 57 times that of the sun.

This kind of binary star system plays a crucial role in the creation of galaxies and it is theorized that they are the main producers of elements like oxygen.

While the interaction between these two stars might resemble the phenomenon of "vampire stars" -- one smaller star sucks out the matter from the surface of the larger star next to it -- both parts of VFTS 352 are of identical size. The researchers hypothesize that rather than taking from one another, the stars might be sharing about 30 percent of their matter.

Given how rare it is to find this kind of star system, the researchers are unsure what the final outcome will be. Lead scientist Hugues Sana, of the University of Leuven in Belgium, said that the final merger of the stars could lead to "one of the most energetic explosions in the universe, known as a long-duration gamma-ray burst."

Lead theoretical astrophysicist Selma de Mink said another outcome is possible.

"If the stars are mixed well enough, they both remain compact and the VFTS 352 system may avoid merging," she said. "This would lead the objects down a new evolutionary path that is completely different from classic stellar evolution predictions. In the case of VFTS 352, the components would likely end their lives in supernova explosions, forming a close binary system of black holes. Such a remarkable object would be an intense source of gravitational waves."