1. Stellar Corpses and Other Space Oddities
Black Holes, Neutron Stars, Nova and other creatures in the stellar zoo

2. End of a Massive Star
Core contracts and becomes neutronized by reverse Beta decay
Collapse either is stopped by degeneracy
Or, for very massive core (3M) collapse isn’t halted

3. Neutron Stars Core Mass 1.4-3M
Very dense ( 1 teaspoon= 1billion tons)
Small in size (10-30km)
STRONG magnetic field
Likely spinning rapidly
Postulated in 1930’s
Not widely accepted until 1968

4. Neutron Stars and Pulsars
Pulsars discovered in 1968
Beaming “pulses” of EM waves at regular intervals
LGM at first!
Lighthouse Model
All Neutron Stars may be Pulsars

5. Lighthouse Model Rotation Axis Beamed Radiation Magnetic Field
Neutron Star

6. Pulsars Millisecond Pulsars Pulsars are slowing
Can be in Binary systems
Maybe a source of X-ray Binaries
Neutron Star is accreting material from companion

7. Black Holes If collapse is not halted Mass collapses to a singularity
Singularity is a point
“Punches a hole” in space-time
Curvature of spacetime
Gravity is extremely strong

8. Black Holes Escape Velocity greater than c
Like standing on a rubber sheet holding an anvil (2D analogy)
Black holes are actually 3D objects
Think Flatland!
Event horizon-boundary between BH and observable universe
Schwarzschild Radius

9. Black Holes Strong Gravity Tidal Forces
Relativity takes over (time slows)
No way to get knowledge from interior
Much indirect evidence for Black Holes
Also form X-ray binaries
Use formula to find mass of unseen companion

10. Black Holes Have No Hair
Matter in a black hole becomes simple in form
Loses all identifying features except
Electric Charge
Mass
Angular Momentum
No protons, electrons, neutron etc

11. Two Types of Black Holes
Schwarzschild Black Hole – “classic” non-rotation
Kerr Black Hole- rotating, can escape from (maybe)
Black Holes may be evaporating from Hawking Radiation

12. Black Hole Binary Systems
Roche Lobe Overflow Wind
X-ray Jets
Black Hole
Companion Star
Accretion Disk

13. Nova A WD in binary system Accretes matter from companion
Gets stellar “indigestion”
Flares up and brightens
Calms back down
Process begins again
Doesn’t disrupt star

14. Type I Supernova Same setup as Nova Accretion occurs much faster
Star can’t “burp” off material
Exceeds Chandre mass
Star begins a rapid collapse w/core bounce
Supernova that completely destroys WD

15. Supernova Comparison Type I much more luminous that Type II
Both form Supernova Remnants (SNR)
Type I have less material in SNR
Material is moving much faster in Type I
Type I have no Hydrogen in spectra
Type II do

16. Hypernova and Gamma Ray Bursts
New idea
Very powerful supernovae
Could be generating BH instead of NS
Collapse of BH leads to Gamma Ray Burst
Gamma Ray bursts are random
No one knows what they are!

17. Summary Massive stars can leave behind unusual corpses
Supernova come in different types