A Type Ia Supernova

Type Ia supernovae take place in close binary systems in which one of the stars is a white dwarf and the other a red giant. If the red giant overflows its Roche lobe, gas from its outer layers piles up on the white dwarf and triggers an explosion that blows the white dwarf apart. This supercomputer simulation shows how the blast wave from the white dwarf (located off-screen above the top of the frame) affects the red giant star (shown near the top of the frame). The colors indicate gas density: dark blue is densest, followed by light blue, green, yellow, and red for the lowest density. In this simulation the shock wave tears away about 15% of the red giant's mass, but the red giant survives nonetheless. The first two-thirds of the simulation shows about an hour of actual time; the final third shows about four and a half additional hours.

Courtesy Evonne Marietta and Adam Burrows (University of Arizona) and Bruce Fryxell (University of Chicago).