An astronomer studies two globular clusters,A and B.Cluster A has a higher metallicity than cluster B,but their properties are otherwise identical.The astronomer should expect that:
A) cluster A's main sequence turnoff occurs at a higher mass than cluster B.
B) cluster A is more distant than cluster B.
C) cluster A is older than cluster B.
D) cluster A is more massive than cluster B.

Question

Quizplus · Accepted Answer

Higher metallicity in stars indicates a younger age because it means the stars have a higher proportion of elements heavier than hydrogen and helium, which are produced by previous generations of stars. Therefore, a cluster with higher metallicity (like cluster A) would have its main sequence turnoff occur at a higher mass, as it is younger and its stars have not yet evolved off the main sequence at lower masses. The other options are not directly related to metallicity.

An Astronomer Studies Two Globular Clusters,A and B