•When
the degenerate core of a star exceeds 1.4 MSun it collapses
–Type
II: Massive star runs out of fuel
after converting core to Fe
–Type I:
White dwarf in binary, which receives mass from its companion (collapse ignites carbon
burning).
–
•Events:
–Star’s
core begins to collapse
–Huge
amounts of gravitational energy liberated
–Extreme
densities allows weak force to convert matter to neutrons
p+ + e- ®
n + n
–Neutrinos
(n)
escape, carrying away much of energy, aiding collapse
–Collapsing
outer part is heated, “bounces” off core, is ejected into
space
•Light
from very hot ejected matter makes supernova very bright
•Ejected
matter contains heavy elements from fusion and neutron capture
–Core
collapses into either:
•Neutron
stars or Black Holes (Chapter 11)