Astronomy Quiz #6

What do astronomers mean when they say that we are all star stuff?

• The earth formed at the same time as the sun.

• That’s the universe contains billions of stars.

• That the sun formed from the interstellar medium the stuff between the stars.

• That the carbon, oxygen, and many elements essential to life are created by nucleosynthesis in stellar course.

Which two energy sources can help a star maintain its internal thermal pressure?

• Nuclear fusion and chemical reactions

• Nuclear fusion and nuclear fission

• Chemical reactions and gravitational contraction

• Nuclear fusion and gravitational contraction

What can we learn about a star from a life track on an HR diagram?

• What surface temperature and luminosity it will have at each stage of its life.

• How long ago it was born.

• All of the above.

• Where it is located.

Which of the following statements about to degeneracy pressure is not true?

• Degeneracy pressure keeps any ProStar less than .08 solar mass from becoming a true hydrogen fusing star.

• Degeneracy pressure arises out of the ideas of quantum mechanics.

• Degeneracy pressure can hold gravitational contraction of a start even with no fusion is occurring in the core.

• Degeneracy pressure varies with the temperature of the star.

All of the following are involved in carrying energy outward from a stars Core except.

• Neutrinos

• Conduction

• Radiative diffusion

• Convection

Which stars have convective cores?

• high mass stars.

• Intermediate mass stars

• All of the above

• None of the above

What happens when a star exhausts it’s core hydrogen supply?

• It contracts, becoming hotter and brighter

• It contracts, becoming smaller and dimmer

• It expands becoming bigger but dimmer

• It’s court contracts but it’s outer layers expand and the star becomes bigger and brighter

What is happening inside a star well it expands into a sub giant?

• It is fusing helium into carbon in the core

• It is fusing hydrogen into helium in a shell outside the core

• It is not fusing any element, it is contracting and heating up

• It is fusing helium into carbon in a shell outside the core

Compared to the star it evolved from, a red giant is.

• The same temperature and brightness

• Hotter and dimmer

• Cooler and dimmer

• Cooler and brighter

Why does a star grow larger after it exhausts its core hydrogen?

• The internal radiation generated by the hydrogen fusion in the core has heated the outer layers enough that they can expand after the star is no longer fusing hydrogen.

• Helium fusion in the core generates enough thermal pressure to push the upper layers outward.

• The outer layers of the star are no longer gravitationally attracted to the core.

• Hydrogen fusion in a shell outside of the core generates enough thermal pressure to push the upper layers outward