1. The Evolution of Massive Stars

2. The Fate of 10, 20, or 30 solar mass stars
Eta Carinae: possibly a 100 solar mass star: what will it do next?

3. The Evolution of massive stars picks up where low mass stellar evolution ends…the C,O core continues to contract
In innermost core, successively hotter nuclear reactions generate heavier nuclei as “ashes” until Iron. This is the peak of the “curve of binding energy”

4. Following iron synthesis, “core collapse” occurs

5. Prediction of core collapse: generation of a Neutron Star
Process of neutronization:
e+p > n + nu
A ball of neutrons the size of Iowa City with the mass of the Sun

6. The Neutron Star
This is the end product of a truly massive star

7. Predicted Consequences of Massive Star Evolution
Huge explosion: 10**44 Joules = total energy radiated by the Sun in its lifetime
Pulse of neutrinos as core collapses
“Pollution” of the interstellar medium as explosion blows off the outer stellar core
Birth of the “neutron star”

8. Prediction #1: Huge explosion = supernova
Simulated appearance of the supernova of 1006 AD…between crescent moon and Venus in brightness for a few weeks

9. The most recent visible supernova: SN1987A
“burst” of neutrinos observed at beginning of supernova explosion

10. “Feature” #3: “Pollution” of the Interstellar Medium
Cassiopeia A: expanding cloud of “metal-rich” debris from a supernova in about 1680: today the brightest radio source in the sky

11. Where is Cas A?
An interstellar dark cloud in front of it prevented a spectacle at the time of the Royal Society

12. Neutron Stars: do they exist?
An object with the mass of the Sun crammed into a ball this big
The end product of massive star evolution

13. Neutron Stars: a brief history
Basic physics understood in the 1930s
At that time, no known counterparts
In the 1950s and 1960s, more and more strange objects found, but where were the neutrons stars, or did they even exist?
The case of the Crab Nebula (supernova of 1054 AD)

14. The Crab Nebula (M1) It’s expanding!

15. For years, the key to the Crab Nebula was there is plain sight
In 1968 the breakthrough came