Numbering some one billion stars (approximately 1% the size of the Milky Way), the Canis Major Dwarf Galaxy is in the process of being pulled apart by the gravitational forces of the larger galaxy it orbits. Long strings of stars beloning the the Canis Major Dwarf form complex, ring-like structures around and through the disc of the Milky Way.
The galaxy was identified in November of 2003 by studying the distribution of M-class stars observed by 2MASS, the Two-Micron All Sky Survey.