Type Ia supernovae

Greedy stars steal from their neighbours until they’re ready to burst

Step 1

Two stars are orbiting one another in a binary star system. One dies to become a dense white dwarf star. Its strong gravity allows it to steal material from its neighbour, increasing its own mass in the process.

Step 2

As the white dwarf’s mass nears the Chandrasekhar Limit, the star shrinks under the new material’s weight. As the pressure and temperature inside both rise, the white dwarf’s carbon and oxygen fuse into iron.

Step 3

This turns the white dwarf into a fusion bomb, which soon detonates as a Type Ia supernovae. It’s a cataclysm so bright that it can be seen halfway across the Universe and it will briefly outshine the entire galaxy it resides in.

Step 4

After the explosion, the supernova will fade over a period of days to weeks. The radioactive decay of ejected material allows us to tell the difference between a Type Ia supernova and other non-standard candles.