Unit Three Study Guide
stronomy -- ASTR 122

The Interstellar Medium:

  1. Compare and constrast the three types of nebulae: Emission, Absorption, and Dark
  2. Decribe the composition of a molecular cloud and how it differs from the types of nebula listed above.
  3. Know how 21-cm radiation is produced and what astronomers can learn by looking for it.
  4. Be able to discuss the geometry nessecary for us to observe an emission and absorption nebula.

Measuring the Stars:

  1. Explain how the spectral absorption lines can be used to identify the elements present in a star.
  2. Be able to explain what the Doppler effect is and what it allows astronomers to measure.
  3. Describe what parallax is and be able to use the parallax angle to calculate teh distance to a star.
  4. Define both apparent and absolute magnitudes and be able to use them to calculate the distance to a star.
  5. Know the limitations of calculating distances with parallax and spectroscopicly.
  6. Be able to sketch the HR Diagram and show what quantities are plotted on the vertical axis and the horizontal axis.
  7. Understand how the surface temperature of a star is indicated by its color. Recall the different colors and relate these colors to their relative temperatures.
  8. Show where the different luminosity classes (Main Sequence, Giants, and Supergiants) are on the HR Diagram.

The Sun:

  1. Recall the layers of the Sun and decribe the role each layer plays.
  2. Detail the Babcock Cycle and explain how it accounts for the 11 year cycle of solar activity.
  3. Explain how sunspots are formed and how prominances and flares related to sunspots.
  4. Recall the surface and core temperatures of the Sun.
  5. Explain the proton-proton chain fusion process.
  6. Know why neutrios produced in the core of the Sun are so important.
  7. Be able to locate the Sun on the HR Diagram.

Stellar Evolution:

  1. Discuss the different phases of evolution of a star such as our Sun.
  2. What is equilibrium in a star?
  3. Know the relationship between stellar mass and stellar lifetime.
  4. State what distinguishes a main-sequence star from giants and supergiants.
  5. What happens in the core of a star when hydrogen fusion ends?
  6. What are the two main facts that set a red giant star apart from a normal star like the sun?
  7. What temperature is required to fuse helium in the core of a star?
  8. What element is formed when helium is fused in stars?
  9. What is a planetary nebula, and how is one formed?
  10. What is a white dwarf, and what is its approximate size and mass?
  11. Discuss the fusion sequence of elements in the cores of massive stars leading to the production of iron.
  12. Explain why iron-fusion absorbs energy instead of producing it.
  13. What is a Type II Supernova, and what causes one to occur?
  14. Discuss what happens to the remnant material from dead stars.
  15. Describe the composition of a neutron star.
  16. How much mass must a dead star's core have to become a neutron star?
  17. Recall the approximate radius of a neutron star.
  18. Describe the structure of a pulsar.
  19. Compare a pulsar with a neutron star.
  20. Compare and contrast the sequence of events in the life of lightweight and heavyweight stars.
  21. Describe under what conditions a star can become a black hole.
  22. How much mass must a dead star's core have to become a black hole?
  23. Why is a black hole called a 'black hole'?
  24. How can a black hole be detected?

Binary Stars:

  1. Recall that the majority of stars in our galaxy are multiple star systems.
  2. Know the three types of binary star systems and what distinguishes each kind.
  3. For the three types of binary systems, explain in which mass transfer occurs and in what direction.
  4. Discuss the meaning of Roche Lobes and how they determine the type of binary system two stars will be.
  5. Describe what the L1 (Lagrange Point) is and how it relates to the Roche Lobes.
  6. Sketch the structure of a Cataclysmic Variable star system.
  7. Explain what a light curve is and what it allows astronomers to measure.
  8. Detail the process in a CV that leads to a dwarf (recurrent) nova.
  9. Be able to use the velocities of the two stars of a binary system and Kepler's Third Law to calculate the mass of the two stars.