Two huge stars are about to collide.
No, we aren't talking about the Grammy Awards after-parties.
Two massive stars in the middle of the planetary nebula Henize 2-428 are about to merge (700 million years from now) and their union will cause a supernova explosion, according to a press release from European Southern Observatory (ESO).
ESO facilities and telescopes in the Canary Islands were used in the identification and the results can be seen in the online journal Nature. Miguel Santander-García from Observatorio Astronómico Nacional, Alcalá de Henares, Spain and Instituto de Ciencia de Materiales de Madrid (CSIC), Madrid, Spain lead the discovery of the white dwarf stars. The stars are very small and dense with a total mass 1.8 times that of our sun.
"This is the most massive such pair yet found and when these two stars merge in the future they will create a runaway thermonuclear explosion leading to a Type Ia supernova," according to the press release.
Initially, the astronomers were looking at a single planetary nebula. "When we looked at this object's central star with ESO's Very Large Telescope, we found not just one but a pair of stars at the heart of this strangely lopsided glowing cloud," said co-author Henri Boffin from ESO.
The theory that the odd shape of some nebulae could be the result of double central stars is supported by these findings.
"Further observations made with telescopes in the Canary Islands allowed us to determine the orbit of the two stars and deduce both the masses of the two stars and their separation. This was when the biggest surprise was revealed," said Romano Corradi, another co-author and researcher at the Instituto de Astrofísica de Canarias (IAC), Tenerife.
The dwarf stars orbit each other once every four hours, and if Einstein was right about that theory of relativity, they will spiral - pulled by gravity - and merge into one massive star that will collapse on itself and explode (as a supernova).
"Until now, the formation of supernovae Type Ia by the merging of two white dwarfs was purely theoretical," said David Jones, coauthor of the article. "The pair of stars in Henize 2-428 is the real thing!"
"It's an extremely enigmatic system," concluded Santander-García. "It will have important repercussions for the study of supernovae Type Ia, which are widely used to measure astronomical distances and were key to the discovery that the expansion of the universe is accelerating due to dark energy."
