Lesson 5 Star Systems and Galaxies

Term Definition
Binary star A star system with two stars
Eclipsing Binary a binary star system in which one star periodically blocks the light from the other
Open Cluster a star cluster that has a loose, disorganized appearance and contains no more than a few thousand stars
Globular cluster a large, round, densely-packed grouping of older stars
Galaxy a huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity
Spiral galaxy a galaxy with a bulge in the middle and arms that spiral outward in a pinwheel pattern
Elliptical galaxy a galaxy shaped like a round or flattened ball, generally containing only old stars
Irregular galaxy a galaxy that does not have a regular shape
Quaear an enormously bright, distant galaxy with a giant black hole at its center