| A | B |
|---|
| apparent magnitude | a star’s apparent brightness |
| absolute magnitude | a star’s actual brightness |
| dwarf star | a small or medium-sized star |
| giant star | a star that can be tens to hundreds of times larger and hundreds of times more luminous than the sun |
| supergiant | a star that is hundreds of times larger than the sun and thousands of times brighter |
| parallax | a way of measuring the distance of stars by observing their apparent movement in relation to other stars |
| variable star | a star that regularly or repeatedly changes in brightness |
| pulsating variable star | variable star that goes through periods of brightening and swelling, then shrinking and diminishing |
| nova | a star that suddenly flares and becomes 100’s to 1000’s of times brighter than normal |
| nebula | a cloud of interstellar gases and debris |
| supernova | the death explosion of a massive star |
| neutron star | a star that has collapsed under its own gravity; it is composed of neutrons |
| pulsar | a neutron star that spins rapidly on its axis |
| black hole | area of extreme gravitational force that may result from the collapse of a massive supergiant |
