What Are the Main General Features That Make Clusters of Stars

question 115

Multiple Choice

What are the main general features that make clusters of stars useful to astronomers?

• A) The stars are at the same distance from Earth,were formed at approximately the same time,and were made from the same chemical mix.
• B) The stars are all at the same distance from Earth,have the same surface temperature,and joined the cluster at various times.
• C) The stars all have the same apparent magnitude,the same surface temperatures,and the same sizes.
• D) The stars all have the same intrinsic brightness but differ in size and surface temperature.