Motion in the HR Diagram
During He core, H shell
burning
Moving some of E generation
back into core shrinks size (and
so raises TSurface)
Eventually He in core runs out
 leaving a C, O core inside the
He region
Core contracts and heats up till
He ignites in shell outside C, O
core
During He shell, H shell
burning
At first R increases, TSurface
decreases
L increases as more C,O
accumulate and TCore continues
to increase