The H-R diagram of a young star cluster shows
A)that high-mass stars have not yet reached the main sequence yet.
B)that low-mass stars have not yet reached the main sequence yet.
C)mainly giant stars.
D)no stars since none have reached the main sequence yet.

Question

Quizplus · Accepted Answer

The H-R diagram of a young star cluster shows that low-mass stars have not yet reached the main sequence yet. This is because low-mass stars take a longer time to reach the main sequence compared to high-mass stars. As a result, they are still in the pre-main sequence phase when the cluster is young. High-mass stars, on the other hand, reach the main sequence relatively quickly and are already there when the cluster is young. Thus, the H-R diagram of a young star cluster will show a lack of low-mass stars on the main sequence.

The H-R Diagram of a Young Star Cluster Shows