Measurements indicate that a certain star has a very high intrinsic brightness (100,000 times as bright as our Sun),yet is relatively cool (3500 K).How can this be?
A) There must be an error in observation because no star can have this form.
B) The star must be quite small.
C) The star must belong to the main sequence.
D) The star must be very large.

Question

Quizplus · Accepted Answer

The star's high intrinsic brightness can be explained if it is very large, as larger stars have higher luminosities. The star's relatively cool temperature can be explained if it is a red giant or a red supergiant, which are both large, cool stars.

Measurements Indicate That a Certain Star Has a Very High