Crossword: Life of a Star

3. all existing matter and space considered as a whole; the cosmos.
4. specifically fusion, are the engine that powers stars
8. the name of the galaxy that our solar system, including Earth, is a part o
11. two or more atomic nuclei combine to form one or more different nuclei, releasing a tremendous amount of energy in the process
12. exceptionally luminous and large, occupying the top region of the Hertzsprung-Russell diagram
13. stars that have a substantially larger radius and luminosity than main-sequence stars
14. a theoretical stellar object that results from a white dwarf cooling down over an incredibly long period
15. type of galaxy characterized by a flattened, disk-shaped structure containing stars, gas, and dust

1. a system of millions or billions of stars
2. the dense, stellar core remnant that remains after a star like our Sun
5. the intrinsic brightness of a celestial object
6. a plot of stars showing the relationship between their luminosity and temperature
7. star that is in the stable, longest phase of its life cycle, characterized by core hydrogen fusion
9. beginning of the life cycle of a star
10. system used to classify stars based on their temperature