Stars

1. variables - Stars with pulsation periods between 1 and 100days and luminosity increases as much as 100 times from the dimmest star to the brightest
3. II stars - Found in the halo and bulge and contain even smaller amounts of heavy elements
5. - A spherical region where globular clusters are located
8. blackhole - A blackhole in the middle of most galaxies
11. Density waves - Spiral regions of alternating density, which rotates in a rigid motion
13. bar - Made up of younger stars and a disk that forms from neutral hydrogen gas.
14. Lyrae Variables - Stars that have periods of pulsation between 1.5hours and 1.2days and on average have the same luminosity

2. I stars - Found in the disk and arms and have small amounts of heavy elements
4. - Light year, a unit for distance
6. stars - Huge spherical star clusters located above or below the plane of the galactic disk, used to estimate distance of clusters by using these stars.
7. bulge - Made up generally of older, red stars
9. - Astronomical Unit, distance from Earth to Sun
10. arms - Birthing area of stars that is subject to gravitational tags and giving it its shape
12. - Any of the very large groups of stars and associated matter found throughout the universe