A star spends most of its life as a main sequence star
Hydrogen fusion 4H -> He
Remember lifetime proportional to 1/M2.5
Low Mass < 2 MSun
Intermediate Mass 2-8 MSun
High mass >8 MSun
Low mass stars have radiative cores and convective upper layers (like the Sun)
Red giants and supergiants
Hydrogen shell burning
Helium Flash
Helium burning
Evolutionary track H-R diagram of an old cluster
Mass loss and thermal pulses
Planetary Nebulae - The quiet way to die
A large beautiful variety 1 2 3 4 5
Summary Luminosity Radius
H fusion is different (but with the same result)
Heavier elements in the core
The trouble with iron – no energy profit
But the core does it anyway!
Star explodes and recycles heavier elements
Supernovae
Where does the energy go?
Ejection velocity
Construction of new elements
The neutron star or black hole magnetic field, spin, heat
neutrinos
If white dwarfs are < 1.4 MSun but started out as large as 8MSun and
Neutron stars are < 3 MSun but started out >8MSun
What happened?
Just when you thought you had it all figured out…..
The binary star Algol = 3.7MSun m-s dwarf and a .8MSun subgiant
