Chapter 12

1. How big is the Sun compared to the Earth?

2. How can we measure the Sun’s size, mass and temperature?

3. What is the Sun made of? How do we know this?

4. What holds the Sun together?

5. Why doesn’t the Sun collapse?

6. Why must the interior of the Sun be so hot?

7. How does energy get to the Sun’s surface from its core?

8. What visible evidence do we have that the Sun has a convective zone?

9. What are the photosphere, chromosphere and corona? Which of these layers is hottest? How do we know this?

10. How is solar energy generated? In what form(s) does it leave the core?

11. Explain the “solar neutrino problem” and how its resolution was a good example of the scientific process.

12. What is solar seismology? What does it tell us about the Sun?

13. What is meant by solar activity?

14. What role does magnetic activity play in solar activity?

15. Why do sunspots appear dark?

16. Ho do a prominence and a flare differ?

17. How do we know there are magnetic fields in the Sun?

18. What is the solar cycle?

19. What is the period between maximum sunspot numbers? How does this differ from the full solar cycle?

20. What is the Maunder minimum? Why is it of interest?

Chapter 13

1. Describe the method of distance measurement by triangulation.

2. How do astronomers triangulate a star’s distance?

3. How is the parsec defined? How big is a parsec compared with a light-year?

4. How do astronomers measure a star’s temperature?

5. What do astronomers mean by an inverse-square law?

6. What is luminosity? What two characteristics of a star determine its luminosity?

7. What does a star’s magnitude measure? Which is brighter, a star of magnitude 1 or a star of magnitude 3?

8. What are the stellar spectral types? Which are hot and which are cool?

9. Why do stars have dark lines in their spectra?

10. What is different about the spectra of different types of stars?

11. What is a binary? How are they useful to astronomers?

12. How do visual and spectroscopic binaries differ?

13. What is an eclipsing binary? What can be learned from eclipsing binaries?

14. What is the H-R diagram? What are its axes?

15. What is the main sequence?

16. How do we know that giant stars are big and dwarf stars are small?

17. How does mass vary along the main sequence?

18. What is the mass–luminosity relation?

19. What is a standard candle and how is it used?

Chapter 14

1. What processes and forces determine the structure of stars?

2. Through what stages will the Sun evolve? Through what stages will a high-mass star evolve?

3. What heats a protostar? How can we observe protostars? Why are they surrounded by dust and gas?

4. What is bipolar flow?

5. What is a T Tauri star?

6. What is a Bok globule?

7. What determines when a star become a main-sequence star?

8. How long do stars stay on the main sequence?

9. What makes a star move off the main sequence?

10. Where do main-sequence stars end up as they evolve?

11. Why is it easier for a high-mass star than for a low-mass star to burn helium?

12. Why do high- and low-mass stars evolve differently as they become red giants?

13. What is a variable star? What is meant by the period of a variable star?

14. Where in the H-R diagram are variable stars found?

15. What is meant by a pulsating star? Why do stars pulsate?

16. What happens to a solar-mass star when it starts to burn helium in its core? What does it turn into?

17. What is a planetary nebula?

18. What is one explanation for how a low-mass star expels its outer layers to make a planetary nebula?

19. What is left when a planetary nebula dissipates?

20. What makes a high-mass star’s core collapse?

21. Why do neutrons form in a massive star’s iron core?

22. What is a supernova explosion?

23. What kind of subatomic particles have been observed when a supernova explodes?

24. How are clusters of stars used to test theories of stellar evolution?

Chapter 15

1. What are the approximate mass and radius of a white dwarf compared with those of the Sun?

2. How does a white dwarf form?

3. What keeps a white dwarf hot?

4. Can a white dwarf have a mass of 10 solar masses? Why? What happens if a white dwarf increases in mass?

5. What is meant by degeneracy pressure? How is it related to white dwarfs and neutron stars?

6. Explain what makes a nova occur.

7. What is a neutron star?

8. What are the mass and radius of a typical neutron star compared with those of the Sun? Can a neutron star have a mass of 10 solar masses?

9. How does a neutron star form?

10. How do we observe neutron stars?

11. What is a pulsar? Does it pulsate?

12. Are all neutron stars pulsars? Are all pulsars neutron stars?

13. What creates the beams of radiation seen in pulsars?

14. What is nonthermal radiation?

15. What happens when a gravitational wave moves? What does it affect? Compare this to how light waves move.

16. What is a black hole? Are they truly “black”? What properties can they have?

17. What is the Schwarzschild radius?

18. Why might the distance to the event horizon of a black hole vary depending on which direction you measure from the center?

19. Can astronomers see black holes? Explain.

20. What is Hawking radiation?