• Electron-capture supernova: electron-eating neon causes star collapse (Kavali IPMU)

Understanding how stars die, and how they form these elusive massive objects has been a favorite task since we began to understand the nuclear processes that drive stars and quantum processes that hold of their degenerate carcasses just 100 years ago. One of our biggest struggles has been in sorting out what happens with stars in the 8-10 solar mass range that may end up forming white dwarfs, but may also explode as supernovae and become neutron stars. Exactly which of these two outcomes occurs is a complex problem that includes understanding how much mass is lost through stellar winds, and sorting out all the nuclear fusion processes in the stellar cores. At this mass, the last stage of a star’s evolution includes the formation of a core rich in Oxygen, Neon, and Magnesium. At this point, the star is  supported through a combination of light pressure from burning shells of Hydrogen and helium, and by electron pressure in the core. In our traditional way of thinking, the ultimate fate of the star is determined by how much mass the star losses while undergoing this final burning. 

In new research from the Kavali institute, scientists postulate that the neon and magnesium in the core can undergo electron capture, grabbing up free electrons and converting them into neutrons, neutrinos, and heat. This drives the Oxygen to ignite radically decreases the electron pressure supporting the core. When this happens, the system … well a supernova is now it’s destiny and a neutron star is certain.

I’d like to point out that this story came with what is the weirdest illustration I have ever seen. It is meant to depict the electrons getting gobbled up, but… it’s weird.