Based on its main-sequence turnoff point, the age of this cluster is
A) less than 1 billion years.
B) about 1 billion years.
C) about 4.5 billion years.
D) about 10 billion years.
E) more than 15 billion years.

Question

Quizplus · Accepted Answer

The main-sequence turnoff point indicates the age of a star cluster. A turnoff point at a lower mass (cooler, redder stars) suggests an older cluster. A turnoff point corresponding to stars like the Sun (G-type) suggests an age of about 10 billion years.

Based on Its Main-Sequence Turnoff Point, the Age of This