Across
- 2. a small very dense star that is typically the size of a planet. It is formed when a low-mass star has exhausted all its central nuclear fuel and lost its outer layers as a planetary nebula
- 3. a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass
- 5. about the size of our sun
- 6. the nebulosity surrounding a star
- 7. a ring-shaped nebula formed by an expanding shell of gas around an aging star
- 10. a region of space having a gravitational field so intense that no matter or radiation can escape
- 11. the star within our solar system that gives life on earth
- 12. any luminous object in the sky is massive and remote
Down
- 1. Any star which is larger than 8 solar masses during its regular main sequence lifetime
- 4. aging giant star which has consumed its core's supply of hydrogen fuel. Helium has accumulated in the core, and hydrogen is now undergoing nuclear fusion
- 8. a celestial object of very small radius (typically 18 miles/30 km) and very high density, composed predominantly of closely packed neutrons
- 9. a very large star of high luminosity and low surface temperature. They are thought to be in a late stage of evolution when no hydrogen remains in the core to fuel nuclear fusion