ClusterEvolution

Cluster Evolution: [Go Back] [Class Notes] Textbook pages 252-253

How'd we figure out how stars evolve?

	No astronomer is old enough to have actually seen a star evolve! However, when we plot a single stellar cluster, where all the stars have the same age and distance, then we get a glimpse of how stars evolve. Cluster at Birth. Stars to the upper left of the diagram are MASSIVE stars. Stars toward the middle, have masses like our Sun. The small stars to the lower right have masses much less than our Sun.
	Cluster after 8 Million years. After just 8 million years, the most massive stars are already running out of fuel! They begin to move away from the Main Sequence as they evolve into Red Supergiant Stars.
	Cluster after 250 Million years. Now, stars a few times the mass of our Sun begin to run out of fuel, and evolve away from the Main Sequence as they evolve into Red Giant Stars.
	Cluster after 3 Billion years. Stars that are just slighty more massive than the sun are now leaving the main sequence.
	Cluster after 10 Billion years. If the Sun were in this cluster, it would now have run out of fuel and begin to leave the main sequence.. If it hasn't already, life as we know it on earth has come to an end. Stars at the bottom of the main sequence, those with a fraction of the mass of the Sun, will live on and on and on and on and on and on and on..... for thousands of billions of years.