Watch: Two White Dwarf Stars Collide and Explode Into a Supernova
Astronomers at the ESO observatory have discovered two white dwarf stars that are in the throes of a deadly dance; they are fated to move closer and closer to each other as a result of their gravitational pull, eventually merging in a white-hot explosion and bursting into a supernova.
[Credit: ESO Observatory]
Pictured above, the two white dwarf stars are in the center of a planetary nebula, called Henize 2-428. The researchers discovered the binary system as a result of the shape of the nebula. Where nebulae produced from one star are usually spherical, the above nebula is ring-shaped. The ESO astronomers then confirmed using spectrograph data that there were signatures from two different stars with a short orbital period of 4 hours, leading them to conclude that they were destined for a violent merger.
Lead author Miguel Santander-Garcia told Sen: "It is unusual but not rare to have a binary system with two white dwarfs. So far we have found half a dozen white dwarf binaries, and estimates indicate they could make up 25 per cent of the total planetary nebulae with binary central stars."
Although the merger won't occur for another 700 million years or so, this artist's impression shows the stars merging into a spectacular supernova, destroying both stars in the process:
The study itself is groundbreaking because it shows that a binary white dwarf star system is capable of producing a particularly powerful supernova. As a result of their large mass (1.8 times the mass of the Sun when combined), their merger will cause an increase in temperature, leading to an unstable system. The merged star will then collapse into itself, forming a Type IA supernova. "That was a theoretical path to produce supernovae until now," said Santander-Garcia.
"The formation of Type Ia supernova is still a great mystery in astronomy," said co-author Henri Boffin. "There are several theories proposed, but as always in science, theory needs to be backed-up by observations. Our observations show for the first time that such systems exist!"