See this page for an attempt to clarify the discussion of nuclear reactions and the connection with stellar evolution. 

There is an informative online description of energy production in all kinds of stars at the following website: http://nrumiano.free.fr/Estars/energy.html

1.

a.  For an introduction to this week's topics, see the week 4 instructor notes.

b.  To read about the long history of discovering brown dwarfs (sub-stellar objects), see the Scientific American article, "The Discovery of Brown Dwarfs," by Gibor Basri:  April 2000, page 76.  The article will help understand "what if" gravitational collapse does not generate high enough temperature in an object to cause hydrogen (protons) to fuse to produce helium (i.e., what stops the gravitational collapse before the temperature gets to 6 million Kelvin?).  For a quick summary of formation of brown dwarfs, see the following page for information I present in class: Brown Dwarf Formation

2.  Respond with written answers to the Week 4 discussion questions.
Assess and self-score your responses by comparing with my responses in class on the due date.

3.  Print out the Week 4 Homework and circle your answer choice for each question. Turn these in the first day of Week 5.