These two stars could kiss for a million years — and then die

 

ESO/L. Calçada

An artist’s impression of VFTS 352, the kissing stars.

Stars dubbed VFTS 352 could merge into one or lead scientists down a new evolutionary path

Ah, young love.
Just like teens on Earth, these two “young” stars, found by astronomers in a real galaxy somewhat far, far away, can’t bear to be parted. Their fate, however, is likely to be like that of Romeo and Juliet: a brutal death.
Scientists say the stars could merge into one and eventually explode — or separate and explode. But it could take 600,000 years — or even a few million years — for that to happen.
The pair of stars, known as VFTS 352, orbit each other in little more than a day about 160,000 light years away from Earth. That’s far even for Han Solo and the Millennium Falcon, and the surface temperature — above 40,000 degrees Celsius — makes it inhospitable for a “Star Wars” colony.
The two stars and their overlapping surfaces are “brightest, hottest, most massive” type of a rare phenomena formally called “overcontact binaries,” said Richard Hook, a spokesman with the European Southern Observatory, which operates three major astronomy sites in Chile. Unusually, the stars are of similar size, and they are estimated to be sharing about 30% of their material
The Tarantula Nebula, where they were found, is an area with clouds of dust, lots of gas and many hot young stars — young being millions of years, rather than the billions of years of our sun. These two stars are estimated to be about 2.5 million to 3.5 million years old.
Tarantula Nebula’s galaxy, the Large Magellanic Cloud, is a satellite galaxy of our Milky Way. It is 50,000 parsecs away from us and is visible from the southern hemisphere with the naked eye and no light pollution. (Han Solo boasted of making the Kessel Run in less than 12 parsecs.)
Amateur astronomers could faintly see the pair with their own telescope, Hook said, “but it would be hard to find and unremarkable to look at.”
The stars were discovered in March 2014 with data compiled by Hugues Sana, a scientist at the University of Leuven, in Belgium, who was then working for the Hubble Space Telescope at the Space Telescope Scientist Institute in Baltimore, and analyzed by Leonardo Almeida, then at Johns Hopkins University and now at the Insitituto de Astronomia in São Paulo, Brazil.
“Understanding the life cycle of massive stars (how they form, live and die) is important for our comprehension of the evolution of galaxies,” Sana said. Studying a binary system like VFTS 352 is a key part of understanding how such massive stars live and die.
So what will happen to VTFS 352? Scientists are still debating the likely answer. Under one scenario, they will merge into a single gigantic star in about 600,000 years. That could then continue spinning rapidly and end its life in another three million or four million years with “one of the most energetic explosions in the universe,” Sana said.
A second possibility is that the stars continue mixing material but avoid merging, leading scientists down a new evolutionary path. Their lives could end in 2 million or 3 million years with supernova explosions that form binary black holes that could eventually merge.
Scientists are now analyzing fresh data from the Hubble telescope and could agree on an answer in about a year, Sana said.