Canis Major is a dwarf galaxy located in the constellation of Canis Major. The galaxy contains a relatively high percentage of red dwarf stars, and is thought to contain an estimated one billion stars in all.
The Canis Major dwarf galaxy is of the classification 'Irregular' and is now thought to be the closest neighbouring galaxy to the Milky Way, being located only 42,000 light-years from the Galactic Center and approximately 25,000 light-years away from our Solar System.
Canis Major was first discovered in 2003, by astronomers conducting the Two-Micron All Sky Survey. The international team of astronomers located the galaxy by conducting an infrafed light survey of the region of the sky occupied by the Canis Major constellation.
Astronomers believe that the galaxy is in the process of being pulled apart by the gravitational field of the more massive Milky Way galaxy. The discovery of the Canis Major dwarf galaxy has provided some support for the current theory that some galaxies grow in size by swallowing their smaller neighbours.
See also: Sagittarius (dwarf galaxy)