ESO astronomers havediscovered a pair of enormous stars, known as an overcontact binarysystem, that orbit so close to each other that a bridge of stellarmaterial has formed. Scientists predict that at some point, thestrange partnership will end in spectacular fashion, with the stellarbodies either merging to create a single titanic star, or in aviolent supernova, that would birth a binary black hole system.
Situated in theTarantula Nebula around 160,000 light-years distant from Earth, VFTS352 is unusual for a number of reasons. For one, the O-type stars that form the system are the most massive everdiscovered, boasting a combined mass the equivalent of 57 Suns, and asurface temperature of around 40,000 ºC (72,032 ºF), making it thehottest overcontact binary system ever discovered. But mostintriguingly, the stars are almost identical in size.
It has been observed inthe past that when O-type stars orbit close enough for a bridge toform, that one of the bodies is significantly larger than the other,resulting in the smaller body siphoning material off of itscompanion, essentially becoming a "vampire star." But inthe case of VFTS 352, the mass of both O-trype stars is incrediblysimilar, meaning that they share around30 percent of their mass in a roughly even manner, so far as we cantell from telescopic observations.
Based on previousobservations of similar binary systems, this stage in the life of thestellar twins is likely to be short-lived, at least in cosmic terms. In time, the close proximity of the stars may result in them mergingto form a single enormous stellar body. In this scenario, the vast,rapidly spinning star would most probably end its life in anenergetic explosion known as a long-duration gamma-ray burst.
The second possibility,predicated on a mixing of material between the two stars interiorsvia powerful tidal forces, would see the stellar bodies explode intwin supernovae, creating a binary system of black holes – anevolutionary path that would exist outside of standard stellarevolution predictions.
A paper on the findingshas been published online in the Astrophysical Journal.
Scroll down to see an animation of the binary system VFTS 352.
Source:ESO
