Dead stars team up for supernova explosions

BUMPER STARS Some type 1a supernovas, such as SN 1006 seen in this composite image, might be the result of two white dwarfs smashing together.
X-ray: NASA, CXC, Rutgers, G.Cassam-Chenaï, J.Hughes et al.; Radio: NRAO, AUI, NSF, GBT, VLA, Dyer, Maddalena & Cornwell; Optical: F.Winkler/Middlebury College, NOAO, AURA, NSF, CTIO Schmidt, DSS
When white dwarfs bump into each other, they aren’t quiet about it. Three powerful explosions known as type 1a supernovas might have been triggered when pairs of white dwarfs smashed into one another, Subo Dong, an astrophysicist at Peking University in Beijing, and colleagues report in the Nov. 21 Monthly Notices of the Royal Astronomical Society.
Researchers debate whether type 1a supernovas are caused by a lone white dwarf (the core of a dead star) or two working together. Dong and colleagues observed pairs of gas clouds racing away in opposite directions from three such explosions. The shrapnel is probably the signature of white dwarf pairings, computer simulations suggest.