Astronomy Stars and Stellar Evolution 5

Question 1

What does a star's luminosity measure?

Accepted Answer

Total energy emitted per unit time

Answer

Luminosity is the intrinsic total power a star radiates, independent of distance.

Question 2

Why do more massive main-sequence stars have shorter lifespans?

Accepted Answer

They burn fuel much faster

Answer

Massive stars consume their fuel at a far higher rate despite having more of it.

Question 3

What is the process by which helium fuses into carbon in aging stars?

Accepted Answer

The triple-alpha process

Answer

The triple-alpha process combines three helium nuclei into carbon in red giant cores.

Question 4

Absolute magnitude describes a star's brightness as seen from what standard distance?

Accepted Answer

10 parsecs

Answer

Absolute magnitude standardizes brightness by placing every star at 10 parsecs.

Question 5

Where in the galaxy are new stars most actively forming?

Accepted Answer

Dense molecular clouds and nebulae

Answer

Cold, dense molecular clouds collapse under gravity to birth new stars.

Astronomy Practice Test