Cassiopeia Dwarf

The Cassiopeia Dwarf (also known as Andromeda VII) is a dwarf spheroidal galaxy about 2.45 Mly away in the constellation Cassiopeia. It belongs to the Local Group and is a satellite galaxy of the large Andromeda Galaxy (M31). Because it appears behind the Milky Way's galactic plane, its light is made dimmer by dust and gas in our own galaxy.

The Cassiopeia Dwarf was discovered in 1998 by astronomers from Russia and Ukraine. Like the Pegasus Dwarf, it is farther from the Andromeda Galaxy than most of its other small companions, but it is still held by the Andromeda Galaxy's gravity. This galaxy does not have any very bright, young stars, and it has not formed many new stars recently. Instead, it is made up mostly of very old stars, some of which are about 10 billion years old. Most of its stars formed around 6.2 billion years ago, and by 5 billion years ago, almost all of its star formation had stopped.