Star and Planetary Nebula

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  • Topic: Star, Sun, Interstellar medium
  • Pages : 3 (615 words )
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  • Published : November 6, 2011
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Exam 2 Study Guide

Chapter 16, Star birth

1. Where are stars born?
2. In percent mass, what does the interstellar medium of our galaxy consists of? 70% hydrogen, 28% helium, 2% heavier elements.
3. What is the most abundant molecule in molecular clouds? Molecular hydrogen
4. What is interstellar reddening?
Dust grains block the bluer wavelength causing reddening on the edges of molecular clouds. 5. What part of the light spectrum is best to view stars within a molecular cloud? 6. What prevents the pressure from increasing as a cloud contracts due to its gravity? 7. How was the first generation of stars different from stars born today? 8. What causes the temperature to rise to the point of nuclear fusion inside a molecular cloud? 9. What happens to the rotation of a molecular cloud as it collapses to form a star? 10. At what point does a protostar become a true star?

Chapter 14, Our star – the sun

1. Why does the sun shine?
2. What is the power source of the sun? What is hydrogen being converted into? 3. What do we mean when we say that the Sun is in gravitational equilibrium? 4. Lists the "layers" of the Sun in the correct order? What are the physical characteristics of each layer? 5. What are sunspots? How do they form?

Chapter 17, Star Stuff

1. Where did the elements heavier than hydrogen and helium come from? 2. Why does a star grow larger after it exhausts its core hydrogen? 3. What does helium fusion produce?
4. Which element has the lowest mass per nuclear particle and therefore cannot release energy by either fusion or fission? 5. What is a helium flash? Why does it occur and how does it affect the star? How is it represented on the H.R. diagram? 6. What is a planetary nebula?

a. From what type of stars are planetary nebula formed and how are they formed? b. How are planetary nebulas represented on the H.R. diagram? c. What happens to a...
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