Galaxy, Irregular
A galaxy of amorphous or chaotic appearance, possessing large clouds of gas and dust, and both Population I and Population II stars, but no spiral arms or nucleus. They are thought to result from a collision with a larger galaxy, pulling them out of shape. Most have relatively low mass (about a hundred million to ten billion stars). About 25% of all galaxies are irregular.
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Development Notes
Text by M. Alan Kazlev
Initially published on 10 November 2001.