As a main-sequence star exhausts hydrogen in its core, its surface becomes___ and its energy output per second (luminosity) becomes ____
A) hotter; larger
B) cooler; larger
C) hotter; smaller
D) cooler; smaller

Question

Quizplus · Accepted Answer

As a main-sequence star exhausts hydrogen in its core, it expands into a red giant, causing its surface to cool and its luminosity to increase due to the larger surface area.

As a Main-Sequence Star Exhausts Hydrogen in Its Core, Its