irregular galaxy

irregular galaxy

noun Astronomy.
a galaxy with no specific form and a relatively low mass.

Origin:
1960–65

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Based on the Random House Dictionary, © Random House, Inc. 2014.
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American Heritage
Science Dictionary
irregular galaxy  
A galaxy that does not have the clearly defined shape and structure of typical elliptical, lenticular, or spiral galaxies. Irregular galaxies typically contain large amounts of gas and dust, and their stars are often young. They account for only a small percentage of known galaxies. Some irregular galaxies are the result of gravitational interactions or collisions between formerly regular galaxies. Many irregular galaxies orbit larger regular ones; the Magellanic Cloud galaxies orbiting the Milky Way are examples. Compare elliptical galaxy, lenticular galaxy, spiral galaxy. See more at Hubble classification system.

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