1. What brings a star to the end of its life?
2. What is the last fuel the Sun will be able to burn ?
3. What chemical element does the Sun make in burning its last fuel?
4. What happens to a low mass star when it finally uses up the helium in its
5. What do astronomers call the shell of ejected gas from certain low mass
6. What happens to the core of a low mass star that ejects its outer layers.?
7. The density of the Sun is presently about 1 gm/cm3. If the Sun's
radius shrank to about the size of the Earth, (About a factor of 100), what would
9. What do astronomers think the core of a massive star is made of when it
reaches the end of its life?
10. Why does a massive star end up with a core so different from that of a low
11. When a high mass star's core collapses the star _________.
12. Why are supernova explosions important for our existence?
13. If a planetary nebula expands at about 20 km/sec, how big in AU's will it
get in 10,000 years? Note: Assume it starts with zero radius and that it expands
at a constant speed. You can take the number of seconds in a year to be
3x107 and the number of km in an AU to be 1.5x108.
14. How does this compare to the size of the Solar System out to Pluto?
15. When a spinning object changes its size, its rotation rate
16. The change in rotation rate of spinning object caused by its size change is
a consequence of
17. The law of conservation of angular momentum states that when an object
of a fixed mass changes its radius R, its rotation velocity, V, will change so that
18. If a spinning object's radius shrinks by a factor of 5, its rotation velocity
19. The Sun rotates now with a rotation speed of about 2 km/sec. If its radius shrank to
the size of the Earth, about how fast would it spin?
The Two beautiful pictures below were taken by David Malin of the Anglo-Australian Observatory.
22. What sort of object is shown in the figure (A) above?
23. What sort of object is shown in the figure (B) above?
24. Which of the following is responsible for making a pulsar pulse?