Deep inside the Tarantula Nebula, some 160,000 light-years from Earth, live a pair of very strange stars.
The two young stars form one of the most extreme stellar binaries yet found - they orbit one another in less than a day. Their orbital embrace is so extreme in fact, that they are embracing; super-heated plasma from their photospheres are physically mixing from one lobe to the other.
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The binary pair, called VFTS 352, was discovered by the European Southern Observatory's Very Large Telescope, which was used to peer deep inside the nebula's star-forming nursery. From these observations, astronomers have found that the hot, bright stars' plasma is overlapping, forming a bridge between the two masses. Their centers are only 12 million kilometers (7.5 million miles) apart.
Known as an "overcontact binary" this bizarre object has a very dramatic future ahead of it. Not only is it the most massive overcontact binary known (with a combined mass of 57 times the mass of the sun), it is also the hottest, burning away with a surface temperature of 40,000 degrees Celsius (or Kelvin).
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Usually, compact binary stars consist of a smaller star with a more massive partner. In this case, the more massive star's gravity pulls matter from its partner - hence the moniker "vampire stars". But VFTS 352 is different; both components are of identical mass, so one star isn't preferentially beefing up on the other's plasma. Astronomers estimate that the pair are actually sharing up to 30 percent of each other's plasma.
"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, of the University of São Paulo, Brazil, and lead author of a new paper published in the Astrophysical Journal. "As such it's a fascinating and important discovery."
Although both components of this massive object are existing in relative harmony for now, that's going to change very soon. According to Almeida's team, both stars will either merge, creating one, massive, fast-spinning star, or alternatively both may go supernova, ultimately creating an extreme black hole binary system.
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If both stars merge as one, it's likely that the whole system will implode, generating the most powerful explosion in the known universe - a gamma-ray burst. But if the second scenario happens, the extreme spacetime environment stirred up by the formation of two closely orbiting black holes would generate powerful gravitational waves.
Either way, this is yet another bizarre stellar discovery that shows just how extreme stellar physics can become in our rich cosmos.