A red giant is cooler and brighter than a main-sequence star of the same mass.

Question

Quizplus · Accepted Answer

A red giant is a star that has exhausted its core hydrogen fuel and expanded to several times its original size. This expansion causes the outer layers of the star to cool, making it cooler than a main-sequence star of the same mass. However, the increased size of the red giant also leads to a much larger luminosity, making it much brighter than a main-sequence star of the same mass.

A Red Giant Is Cooler and Brighter Than a Main-Sequence