supernova: five stages in the death of a star

Supernova: Five Stages in the Death of a Star

1. Just before explosion

A red super-giant starapproaches the end of itslife. There is no more fuelto burn and make it shine.Soon its massive densecore is bound to collapseunder its own weight.

2. The first light flash

The core collapses andsends a shock wave out.For a few hours the shockcompresses and heats theenvelope, thus producinga very bright flash of lightfrom the inside of the star.

3. The flash has gone

After hitting the surface at50 million km/h the shockblows the star apart. Thecore turns into a neutronstar, a compact atomicnucleus with the mass ofthe Sun but 10 km in size.

4. The proper Supernova

The hot glowing surfaceexpands quickly makingthe fireball brighter again.In a few days it will be 10xthe size of the original starand will be discovered bysupernova hunters.

5. A long time after

The remains of the formerstar are spread over lightyears of space. They keepfloating quickly, sweepingup interstellar gas hereand there, leaving a faintbeautiful glow behind…

Schawinksi, Justham, Wolf, et al.: “Supernova shock breakout from a red supergiant”, published in Science 2008

Host galaxy Flash Supernova

Sources• Image of Veil Nebula a.k.a.

Cirrus Nebula by JohannesSchedler and taken fromwww.universetoday.com/am/uploads/veil_lrg.jpg

• Illustrations and text byC. Wolf

• Image composition byK. Schawinski

• Image sources (all data arepublic archives)– Host galaxy NASA/HST,

taken by COSMOS team– Supernova NASA/GALEX