20.1	Leaving the Main Sequence
20.2	The Evolution of a Sun-like Star
	Death of the Sun Part I
	Death of the Sun Part II
20.3	The Death of a Low-Mass Star
	Formation of Helix Nebula
	Formation of Knots in Helix Nebula
	Bipolar Planetary Nebula
	H—R Diagram Tracks Stellar Evolution
20.4	Evolution of Stars More Massive than the Sun
20.5	Observing Stellar Evolution in Star Clusters
20.6	The Evolution of Binary-Star Systems
	Chapter Review