Chapter 30 Vocab

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Across
  1. 3. They are very big black holes that occupy the center of most galaxies. They usually have masses of a few million to a few billion times the sun.
  2. 8. They are located in the giant branch of the HR Diagram. They pulsate in brightness because of expansion and contraction of their outer layers. They are brightest at their largest diameters and dimmest at their smallest ones.
  3. 10. light years
  4. 12. stars that have periods of pulsation between 1 and 100 days. And luminosity increases as much as 100 times from dimmest to brightest star
  5. 13. astronomical unit. Distance from the earth to the sun
Down
  1. 1. Distribution of stars in the shape of a flattened ball that surrounds the nucleus of a spiral galaxy. It is at the center of the disk. Usually made of older red stars.
  2. 2. a spherical region where globular clusters are located. It’s located around the nuclear bulge and disk.
  3. 4. Stars in the disk or arms and have small amounts of heavy elements. They are younger stars.
  4. 5. Stars in the halo or bulge and have even smaller traces of heavy elements. They are older stars.
  5. 6. any of the large group of stars and associated matter found in the universe
  6. 7. spiral regions of alternating density that rotate as a rigid pattern. They help galaxies keep their spiral shape.
  7. 9. stars that have periods of pulsation between 1.5 hours and 1.2 days, and on average have the same luminosity.
  8. 11. Are the main production center of young stars, they are the regions of stars that extend from the center of spiral and barred spiral galaxies