Just as a low-mass main sequence star runs out of fuel in its ...

[fox]

Just as a low-mass main sequence star runs out of fuel in its core, it actually becomes brighter. How is this possible?
 
  A) Helium fusion gives more energy than hydrogen fusion does, based on masses.
  B) Its outer envelope is stripped away and we see the brilliant core.
  C) The core contracts, raising the temperature and increasing the size of the region of hydrogen shell-burning.
  D) It explodes.
  E) It immediately starts to fuse helium.

Question 2

What role do the observed irregularities in our solar system play in developing models of planetary formation?
 
  A) They are irrelevant to models of planetary formation.
  B) They help confirm models that lead to random encounters.
  C) They help reject models that allow for moons to have retrograde orbits.
  D) They help reject models that allow for hot Jupiters.
  E) They indicate that the condensation model is the only possible explanation of how solar systems form.

[mrphibs]

Answer to Question 1

C

Answer to Question 2

B

[fox]

Thank you!

[mrphibs]

Always glad to help...