Astronomy

3. Stars whose temperature and luminous place them on the main sequence of the HR Diagram
4. A measure of an object's luminosity
7. A measure of the apparent brightness of an object in the sky
8. A rapidly rotating disk of material that gradually rotates inward as it orbits a starlike object
9. A cloud of gas in space, usually one that is glowing
10. An object too small to become an ordinary star, resulting in fusion failing to start in its core
11. Waves, predicted by Einstein's general theory of relativity, that are created by changes in a local gravitational field and cause distortions in spacetime as they propagate outward through the universe at the speed of light
12. The explosion of a star
13. The brightest type of active galactic nucleus
15. A neutron star from which we observe rapid of radiation as it rotates
16. The hot, compact corpse of low mass stars
18. A forming star that has not yet reached the point where sustained fusion can occur in its core

1. The compact corpse of a high mass star left over after a supernova
2. A giant star that is red in color
5. A glowing, expanding cloud of debris from a supernova explosion
6. A bottomless pit in spacetime. Nothing can escape from within a black hole, and we can never again detect or observe an object that falls into a black hole
14. A large glowing ball of gas that generates energy through nuclear fusion in its core
17. A graph plotting individual stars as points, with stellar luminosity on the vertical axis and spectral type (or surface temperature) on the horizontal axis