Problem
A. Suppose a main-sequence star suddenly started burning hydrogen at a faster rate in its core. How would the star react? Discuss changes in size, temperature, and luminosity.
B. When a star leaves the main sequence, its luminosity increases tremendously. What does this increase in luminosity imply about the amount of time the star has left or the amount of time the star spends on any subsequent part of its evolutionary path? Explain.
C. As an AGB star evolves into a white dwarf, it runs out of nuclear fuel, and one might argue that the star should cool off and move to the right on the H-R diagram. Why does the star move instead to the left? Explain!
D. The intersection of the Roche lobes in a binary system is the equilibrium point between the two stars where the gravitational attraction from both stars is equally strong and opposite in direction. Is this an example of a stable or unstable equilibrium? Explain!
E. In Latin, nova means "new." Novae as we now know, are not new stars. Explain how novae might have gotten their name and why they are really not new stars?