Suppose that,when the stars in a particular open star cluster are plotted in a Hertzsprung-Russell diagram,the turnoff point is at an absolute magnitude of +3.What is the approximate age of this cluster? (See Figure 11-28,Comins,Discovering the Essential Universe,6th ed.)

Question

Quizplus · Accepted Answer

The turnoff point in the Hertzsprung-Russell diagram is a measure of the most massive stars still on the main sequence. The age of a star cluster can be estimated from the turnoff point using theoretical models of stellar evolution. From Figure 11-28 in the textbook, we can see that a turnoff point at an absolute magnitude of +3 corresponds to an age of around 4 billion years. Therefore, the best choice is C.

Suppose That,when the Stars in a Particular Open Star Cluster