Answer Following Questions from the Textbook

Astronomy 1 ID: ______Name: ______

Astronomy 1 Homework #5

Answer following questions from the textbook.

3. Astronomers find that 90% of the stars observed in the sky are on the main sequence of an H–R diagram; why does this make sense? Why are there far fewer stars in the giant and supergiant region?

9. Certain stars, like Betelgeuse, have a lower surface temperature than the Sun and yet are more luminous. How do these stars produce so much more energy than the Sun?

11. Why are star clusters so useful for astronomers who want to study the evolution of stars?

20. Where did the carbon atoms in the trunk of a tree on your college campus come from originally? Where did the neon in the fabled “neon lights of Broadway” come from originally?

4. How do the two types of supernovae discussed in this chapter differ? What kind of star gives rise to each type?

6. If the formation of a neutron star leads to a supernova explosion, explain why only three of the hundreds of known pulsars are found in supernova remnants.

7. What is an event horizon? Does our Sun have an event horizon around it?

16. Arrange the following stars in order of their evolution: A. A star with no nuclear reactions going on in the core, which is made primarily of carbon and oxygen. B. A star of uniform composition from center to surface; it contains hydrogen but has no nuclear reactions going on in the core. C. A star that is fusing hydrogen to form helium in its core. D. A star that is fusing helium to carbon in the core and hydrogen to helium in a shell around the core. E. A star that has no nuclear reactions going on in the core but is fusing hydrogen to form helium in a shell around the core.

You do not have to write down the problems. This homework is due on 11/7.