10
Expected
Evolution of the HR Diagram
for a Cluster
•A
cluster consists of stars which all started to form at the same time (collapsing from the same fragmenting molecular cloud)
•Higher
mass stars contract to main sequence before low mass ones reach it
•Higher
mass stars are also the first to run out of H and leave the main sequence, becoming
supergiants.
•As
time continues, lower and lower mass stars move off the main sequence (at the moving “turn off point”)
The original supergiants don’t live very long.
The lower mass stars produce giants
The original supergiants don’t live very long.
The lower mass stars produce giants
From our text: Horizons, by Seeds