chapter 15

3. the brightness that a star would have at a distance of 32.6 light years from earth
6. Has a bulge at the center and spirals arms
7. Galaxy made up of many stars and looks like a snowball
8. a graph that shows the relationship between a stt surface temputure and absoulut magnitude
11. No clear shape.
15. after a supernova the center of a collapsed star may contract into a tiny ball of neutrons
17. a large group of gas,dust, and millions of stars

1. a ball of gas and dust,gravity pulls the gas and dust together and its center gets hotter
2. a main sequence star that uses all it hydrogen up and can no longer make energy
3. the brightness of a star as seen from earth
4. large cloud of gas and dust
5. a neutron star spinning
9. the lrftover of a red giant, its a small,hot,and dim star that can shine for a billion years
10. the universe began with a hugr explosion
12. the distance that light travels in a year, about 9.64 trillion kilometers
13. contraction of massive fource of gravity
14. a gigant explsion in which a massive star collapses and throws its outer layers into space
16. The band of colors produed when white light passes through a prisme