Astronomers find stars kissing each other to death

21 Oct 2015

An artist's impression of VFTS 352, via ESO/L. Calcada

Astronomers have discovered the hottest, largest double stars ever to be ‘kissing’, so close to each other that an impending doom looms large in their near future.

Destined for a “chemically homogenous evolution”, scientists believe that the duo – called VFTS 352 – is overheating to a huge degree thanks to their incredibly close proximity to each other.

So they’ll either merge into one bigger star or explode into a supernova of destruction and maybe, just maybe, become a black hole.

Located not far from the Tarantula Nebula(well, 160,000 light-years away), VFTS 352 is in an area known by astronomers to be rich in new stars.

The duo are so close together that they orbit each other in under a day. Their centres are just 12m kilometres apart, with a bridge of energy forming between them as they spin.

For scale, the duo, together, dwarf our sun 57 times over. In some instances like this, “vampire stars” (the smaller of the duo) suck energy from the larger and eventually consume them.

Here, though, they’re the same size, sharing around 30pc of their total energy. Stars don’t have the components that each of these show for very long so, for two to be so close together, going through it at the same time, is a first.

A long-duration gamma-ray burst

“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 on the paper. “As such it’s a fascinating and important discovery.”

The end game for this loving duo will be cataclysmic, for sure, but will go one of two ways. They could combine into one rapidly rotating, magnetic gigantic star.

“If it keeps spinning rapidly it might end its life in one of the most energetic explosions in the universe, known as a long-duration gamma-ray burst,” said the lead scientist of the project, Hugues Sana.

Alternatively, and far more entertainingly, they may remain compact without merging.

“This would lead the objects down a new evolutionary path that is completely different from classic stellar evolution predictions,” said Selma de Mink.

In this case, they would probably end their lives in supernova explosions, forming a close binary system of black holes.

Were this to happen, it would be the first time astronomers have ever recorded such an occasion.

Gordon Hunt was a journalist with Silicon Republic