‘Now we understand what’s required to explode a supernova’ – NASA

21 Mar

The new data come from NASA’s Swift satellite, orbiting the Earth and sending back observations of short-wavelength radiation from Type Ia super-mega-explosions afar off in the deeps of space.

“Now, thanks to unprecedented X-ray and ultraviolet data from Swift, we have a clearer picture of what’s required to blow up these stars,” says Stefan Immler, NASA astrophysicist involved in the research.

It’s well known among astro-boffins that Type Ia supernovae originate with a remnant star called a white dwarf, which detonates when pushed to a critical mass. Just what’s required to happen in the run up to the explosion, however, has been harder to pin down.

Dust-mistery

Two main scenarios had been considered possible: in one, the white dwarf sucks in and gobbles up matter from a companion normal star, so gaining mass until, overstuffed, it blows up with unimaginable violence. Alternatively, two white dwarfs might collide like vast hypermassive billiard balls leading to a cataclysmic blast.

In between sniffing gamma-ray bursts emitted from faraway black holes (its main task) Swift has been used to probe Ia supernovae. In two separate studies, featuring 60-odd of the superviolent blasts, boffins couldn’t find any of the types of X-ray or ultraviolet emissions which would indicate that a giant star had been present at the explosion site – the immolation of such a vast star would cause a noticeable amount of these wavelengths to be produced.

Stari

Thus, the scientists conclude, if a companion star is present when Type Ia supernovae kick off, it is generally smaller than our own Sun – indeed, these results could suggest that the dwarf-conkers theory is actually the correct one.

 

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http://www.theregister.co.uk/2012/03/21/nasa_swift_supernova_findings/

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