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 is part of the Local Group and is a satellite galaxy of the big Andromeda Galaxy (M31). We see it behind the Milky Way, so dust and gas in our galaxy make it look dimmer.

The Cassiopeia Dwarf was found in 1998 by astronomers from Russia and Ukraine. Like the Pegasus Dwarf, it is farther from the Andromeda Galaxy than most of its small neighbors, but the Andromeda Galaxy still holds it with its gravity. This galaxy does not have many bright, young stars. It is mostly made 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 almost all new star formation stopped about 5 billion years ago.