| A | B |
|---|
| Black Hole | an area in space that is so dense that nothing, including light, can escape its gravitational pull |
| Chromosphere | the orange-red layer above the photosphere of a star |
| Convection Zone | layer of a star where hot gas moves upward toward the surface and cooler gas moves deeper into the interior |
| Corona | the wide, outermost layer of a star's atmosphere |
| Giant Star | a star with a much larger radius and luminosity than a main sequence star of the same surface temperature |
| Hertzsprung-Russell Diagram | a graph that plots luminosity v. temperature of stars |
| Main Sequence Star | a star that fuses hydrogen into helium in its core |
| Nebula | a cloud of gas and dust |
| Photosphere | the apparent surface of a star |
| Planetary Nebula | a nebula that forms after helium in a star's core is gone and the star casts off its gases |
| Protostar | a cloud of fas and dust in space that develops into a star |
| Radiative Zone | a shell of cooler hydrogen above a star's core |
| Star | a large ball of gas held together by gravity with a core so hot that nuclear fusion occurs |
| Supernova | an enormous explosion that destroys a star |
| White Dwarf | a star that forms as the core of a giant star no longer supports fusioni and the star's outer layers escape into space, leaving a hot and dense core |
