Virgo Stellar Stream

The Virgo Stellar Stream, also known as Virgo Overdensity, is a stellar stream thought to be the remains of a dwarf spheroidal galaxy that is in the process of merging with the Milky Way.

The number of stars in the stream is not greatly in excess of a star cluster, and it has been described as "a rather pathetic galaxy", in comparison to the Milky Way. Many of the stars have been known for centuries and thought of as normal Milky Way stars, although they have a lower metallicity than normal Population I stars in the Milky Way.

The stream lies within the Milky Way, extending over a region of space at least 10 kpc across in three dimensions. It is possible that the Virgo Stellar Stream is a remnant left behind by the disruption of the Sagittarius Dwarf Galaxy as it has orbited around the Milky Way. The Virgo Stellar Stream also resembles the Monoceros Ring, which has similarly been attributed to the Canis Major Dwarf Galaxy merging with the Milky Way.