[petuniasevan]

The classic supernova that we all know (Type II) results from a massive star running out of fusion fuel. This usually leaves a remnant: neutron star or black hole, depending on the star's mass.

The above photo is a different mechanism. A member of a binary star goes through its life, but is not massive enough to supernova. Instead it loses mass (which the other star may accumulate) after becoming a red giant. All that is left is the white dwarf. The other star is now bigger than before if it got some of the now-white dwarf's matter. If it sweeps up enough stellar material it may become big enough to spill over into the white dwarf's gravitational well. As the material swirls off the larger star, it heats up then is pulled onto the white dwarf's surface. If enough accumulates, it becomes unstable and results in a thermonuclear explosion. Some white dwarfs do this on a repeating basis; we call them recurrent novae. But if the material accumulates to a great degree, it may trigger a much more massive explosion that rips the white dwarf to shreds. That's the Type 1a supernova.

Mechanism for Type 1A Supernova Explosions

In a Type IA Supernova, accretion is thought to be onto a white dwarf, but at a rate different from that for a nova. Instead of igniting a thin surface layer, as in the white dwarf, in this case the star becomes unstable and essentially the entire star is consumed in a gigantic thermonuclear explosion.

This may be likened to the explosion of a hydrogen bomb approximately the size of the Earth but containing the mass of the Sun.

[petuniasevan]

[GodBlessRonaldReagan]

Nice!

[foolish-one]

Thank you for feeding my mind and pleasing my eyes.

[SuziQ]

What an awesome picture! It looks almost like a surreal depiction of a drop of water.

[graycamel]

hydrogen bomb approximately the size of the Earth

Saddam would salivate if he reads that. :)

[BossyRoofer]

Great job APOD, keep up the good info!