We know that the Pleiades star cluster is relatively old, about 50 million years old. Each of the following helps us to date the Pleiades EXCEPT ONE. Which is the EXCEPTION?

Question

Quizplus · Accepted Answer

The presence of O and B stars, which are very massive and have short lifespans, suggests a relatively young age for a star cluster. If the Pleiades were older, these types of stars would have already evolved off the main sequence. Therefore, the presence of an O and B star association does not help in dating the Pleiades as being about 50 million years old; it suggests a younger age, making it the exception.

We Know That the Pleiades Star Cluster Is Relatively Old