Astronomy homework questions. Please help!!!!!?

If you're not POSITIVE about one of them, then please let me know!








1. The main method of energy generation in protostars is


a. hydrogen fusion


b. nuclear fission


c. static discharge


d. gravitational collapse


e. trick question, protostars do not generate energy








2. As a star exhausts hydrogen in its core, it


a. becomes hotter and more luminous


b. becomes cooler and more luminous


c. becomes hotter and less luminous


d. becomes coller and less luminous


e. it becomes larger in radius and hotter.








3. A star will experience a helium flash if


a. it is more massive than about 6 solar masses


b. its core contains oxygen and helium


c. its mass on the main sequence was less than 0.1 solar masses


d. it is a supergiant


e. its core is degenerate when helium ignites





4. The main factor controlling the evolution of a star is


a. the star's temperature


b. the star's radius


c. the star's mass


d. the star's color


e. the type of fusion in the star

Astronomy homework questions. Please help!!!!!?
Wow, I love tests.


1. d. Heat from condensation powers a protostar, fusion later.


2. a. Not too sure, though. The core does get hotter, but the outer layers expand and get cooler.


3. e. Degeneracy in the core prevents further collapse, but increases temperature to the point where helium ignites.


4. c. A star's mass is the main factor. Heavier elements can also effect some properties, but to a lesser degree.
Reply:1 d. Gravitational collapse. This process continues for roughly a million years with stars of 1 solar mass, before fusion begins.





2. e. The star expands and liberates more energy.





3. e. http://en.wikipedia.org/wiki/Helium_flas...





4. c.