A star whose mass is 5 times larger than the Sun's and whose luminosity is 100 times larger than the Sun's has a main sequence lifetime about
A) 5 times longer than the Sun's.
B) 500 times longer than the Sun's.
C) 5 times shorter than the Sun's.
D) 100 times shorter than the Sun's.
E) 20 times shorter than the Sun's.

Question

Quizplus · Accepted Answer

The main sequence lifetime of a star is roughly proportional to its mass divided by its luminosity. For a star with 5 times the Sun's mass and 100 times the Sun's luminosity, its lifetime is (1/20)th of the Sun's, or 20 times shorter.

A Star Whose Mass Is 5 Times Larger Than the Sun's