Stars

2. a cloud of interstellar dust or gas or both, which collapses on itself as a result of its own gravity
5. a sudden eruption of particles and radiation from the surface of the Sun
7. relatively cool, dark spots appearing on the surface of the photosphere
9. top layers of the Sun’s atmosphere
10. energy output from the surface of a star per second, measured in watts
12. a nuclear reaction in which an atomic nucleus splits into smaller, lighter nuclei releasing energy
13. brightness an object would have if it were placed at a distance of 10 pc
14. a stream of high-speed, ionized particles flowing outward through the solar system from the Sun's corona

1. a nuclear reaction in which lightweight nuclei combine into heavier nuclei
3. ancient Greek classification system based on how bright a star appears to be
4. small, extremely dense remnant of a star whose gravity is so immense that not even light can escape its gravity field
6. group of stars that forms a pattern in the sky
8. two stars gravitationally bound together and orbiting about a common center of mass
11. massive explosion that occurs when the outer layers of a star are blown off