ast 112 test 3 study guide

ast 112 test 3 study guide -...

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http://localhost:8888/classes/ast112/exam3stu. .. 1 of 3 7/12/08 11:46 PM AST 112 Mon-Wed-Fri 9:40 to 10.30am STUDY GUIDE FOR EXAM 3 Chapter 11: Star Formation 1. Note that some of the material in the first part of this chapter overlaps with the material in Chapter 10. 2. Stars are born in Giant Molecular Clouds like the Orion Nebula. 3. Skip the material on page 239. 4. Free-fall contraction is the star obtaining energy from its collapse - or contraction - under its own gravity. I dropped the book in class to demonstrate this. 5. What is a protostar? Pre-main sequence star? What is meant by the cocoon stage? As the protostar collapses, it is rotating which causes it to flatten into a disk with a bulge at the center called a protostellar disk. (see Figure 11-4) 6. What is meant by the birth line? How long did it take the Sun to contract to the main sequence? How long for a 30 solar mass star? Look at figure 11-6. 7. What is a T-Tauri star and where is it found? What is a T-association? An O Association? A Herbig-Haro object? Look at the material on pages 242-243. 8. A bi-polar flow is gas ejected from both the north and south rotation poles of the protostar. 9. What is HH 30? What is 30 Doradus? 10. Look at the material on pages 244-245 How do we know that NGC 2264 is a young cluster? 11. Back to stellar energy sources. What is the CNO cycle? Carbon acts like a catalyst in this cycle. 12. What are the three processes that transport energy in the interior of a star? Look at Figure 11-11. 13. What is meant by the “opacity” of a gas? 14. Where is convection important in our own sun? In a 20 solar mass star? Look at Figure 11-14. 15. Hydrostatic equilibrium means that all the layers in a gas or fluid are in balance: Pressure balances the pull of gravity. You feel an increase in pressure as you dive to deep layers in a lake or the ocean. 16. What is meant by the onion skin model of a star?
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This note was uploaded on 07/12/2008 for the course AST 112 taught by Professor Timmes during the Spring '08 term at ASU.

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ast 112 test 3 study guide -...

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