What is the lifetime of a star of 0.1 solar masses and a luminosity of 0.01 that of the Sun? Assume the lifetime of the Sun is 10 billion years.
A)100 billion years
B)10 trillion years
C)10 billion years
D)10 million years
E)This star will never start hydrogen fusion reactions because it is not massive enough.

Question

Quizplus · Accepted Answer

The lifetime of a star can be estimated by comparing its mass and luminosity to those of the Sun. A star with 0.1 solar masses and a luminosity of 0.01 that of the Sun will burn its fuel more slowly than the Sun. Since luminosity is a key factor in how quickly a star consumes its fuel, a star with 1/100th the luminosity of the Sun will last much longer. The formula for estimating the lifetime of a star is proportional to its mass divided by its luminosity. Therefore, $10 \times 10 = 100$ billion years, making option A correct.

What Is the Lifetime of a Star of 0