Starts With A Bang!

White dwarfs don’t burn anything, and are only “white” because they emit light due to the energy released from contracting gravitationally. (For a size comparison, the radius of Earth is 6371 km.) When they’re done shrinking after a few billion more years, they stop emitting light, and become known as black dwarfs. But the most massive stars with iron cores, about 8 times the mass of the Sun or more, go supernova. When they start to contract, the pressure on the iron core becomes so intense that it starts to fuse the protons and electrons found in the iron atoms into neutrons! This causes a tremendous release of energy, known as a supernova explosion:

If the star is even more massive, the supernova can become even more powerful, and is known as a hypernova. Perhaps the most massive stars, dozens or even a hundred times as massive as our Sun, will go hypernova.

But maybe not! Astronomers from Ireland have been tracking exploded stars with the Hubble Space Telescope. They’ve been trying to determine what the masses of stars were before they went supernova, by trying to identify which star it was that exploded. Based on their findings, they’ve found that some stars may be massive enough that they don’t go supernova or hypernova, but instead, when they stop burning their fuel, collapse directly into a black hole! Now this is neat, because in theory it isn’t the most massive stars that do this, since their radii will be large enough that they won’t directly collapse into black holes, but some special mass range. Here’s a diagram I’ve found to illustrate the different possible fates of stars, based on their starting mass:

Now, what I want to know is, will the most massive stars in our galaxy, Eta Carinae, the Pistol Star, and LBV 1806-20, go hypernova when they die, or collapse directly to black holes? It might depend on where they are relative to the Eddington Limit, but for all we’re sure of at this point, it might as well depend on whether they’ve read their Dylan Thomas or not!