Suppose you measured H-R diagrams for the two star clusters pictured below. Which of the following statements is true?

Question

Quizplus · Accepted Answer

We can determine the age and distance of the clusters by looking at their position on the H-R diagram. The main sequence turnoff point (where stars are leaving the main sequence and evolving into red giants) is a reliable indicator of a cluster's age. The turnoff point for Cluster A appears to be closer to the top of the diagram, indicating that the cluster is older. Cluster B has a turnoff point further down the main sequence, meaning it is younger.

Additionally, we can use the clusters' positions on the diagram to estimate their distances. The brighter a star, the closer it is to us. Cluster A appears to have brighter stars than Cluster B, suggesting that it is closer to us.

Therefore, the correct statement is that Cluster A is older and closer than Cluster B. (D)

Suppose You Measured H-R Diagrams for the Two Star Clusters