1. Supernova

2. At 15 MK carbon can fuse with four hydrogen nuclei to create more helium. At 100 MK carbon can directly fuse with helium to form oxygen. Both processes release photons. Carbon Fusion photons and neutrinos carbon-12 carbon-12 oxygen-16

3. High mass stars continue beyond helium and carbon fusion. Higher temperatures Higher pressures Deeper layers Iron is stable and doesn’t fuse without massive added energy. Fusion steps Hydrogen to helium Helium to carbon Carbon to oxygen Oxygen to neon Neon to silicon Silicon to iron Core Fusion

4. Degenerate electrons • The nuclei from fusion are separated from their electrons. • Very close degenerate electrons • During core fusion degenerate electrons build up. • Electric charge opposes gravity • Opposing forces create enormous stress inward force of gravity outward force of electrons

5. A supergiant changes temperature becoming more luminous. More than 8 M Core collapses more Charge loses to gravity This becomes a type II supernova. Death of Supergiants supernovae Sun

6. When gravitational force exceeds the electron repulsion, the core collapses immediately. Energy in photons and neutrinos The outward energy hits collapsing material and the star explodes. Stellar Explosion

7. Binary Explosions • A binary can transfer gas from a giant to a white dwarf. • Increases white dwarf size • Gravity exceeds electron repulsion • It will explode into a type I supernova. • Brighter than type II white dwarf supernova giant star gas pulled to partner

8. Supernova Remnants • The supernova core collapse is at 200 billion K. • Photon energies enough to break up iron nuclei • Broken nuclei fuse with iron to create heavy elements. • This matter goes to form new stars and planets.