Witness VFTS 352, the hottest and most enormous “over
contact binary” star system ever found. The two stars, which are so adjacent
that they’re actually touching, feature a mutual mass 57 times that of our Sun.
Astronomers say it’s a distinctive stellar relationship that will end in a
rather histrionic finish. This remarkably large contact binary was spotted by
an international group of astronomers using the ESO’s Very Large Telescope. Situated
160,000 light-years away, it’s consist of two twin stars that orbit each other
in a slight over 24 hours. The stars are so close to each other that their
surfaces overlap, making a stellar bridge between them. Extraordinarily,
their cores are only 7.4 million miles (12 million kilometers) apart (that’s approximately
20 lunar distances). With a mass 57 times greater than our Sun, and a boiling
surface temperature more than 40,000 degrees Celsius, it’s the hottest and most
gigantic over contact binary ever spotted.
![]() |
Image Credit: (ESO/L. Calçada) |
Due to their unstable nature, binary systems like
these obviously don’t last long. Astronomers are truly quite lucky to have spotted
this system, which can meet its end in one of two ways.
The first potential consequence is the unification
of the two stars, which would likely yield a swiftly rotating, and probably
magnetic, enormous single star.
The second possibility is clarified by the chief theoretical astrophysicist in the group, Selma de Mink of University of
Amsterdam: “If the stars are mixed well enough, they both remain compact and
the VFTS 352 system may avoid merging. 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.”