If the stars at the turnoff point of a cluster have a mass of 3 M , what is the age of the cluster?

Question

Quizplus · Accepted Answer

The age of a cluster can be determined using the main sequence turnoff point, which is the point on the Hertzsprung-Russell diagram where the most massive stars are still burning hydrogen in their cores, while less massive stars have already exhausted their fuel and evolved off the main sequence. The mass of stars at the turnoff point is directly related to the age of the cluster, with more massive stars burning through their fuel faster and evolving off the main sequence earlier than less massive stars. Therefore, by knowing the mass of stars at the turnoff point, we can estimate the age of the cluster. For a cluster with stars of 3 M , the estimated age is around 6.4 × 10⁸ years. Therefore, the best choice is C.

If the Stars at the Turnoff Point of a Cluster