| Cassiopeia Dwarf | |
|---|---|
Cassiopeia Dwarf by HST/WikiSky |
|
| Observation data (J2000 epoch) | |
| Constellation | Cassiopeia |
| Right ascension | 23h 26m 31.0s[1] |
| Declination | +50° 41′ 31″[1] |
| Redshift | -307 ± 2 km/s[1] |
| Distance | 2.58 ± 0.13 Mly (790 ± 40 kpc)[2][3] |
| Type | Sph?[1] |
| Apparent dimensions (V) | 2′.5 × 2′.0[1] |
| Apparent magnitude (V) | 12.9[1] |
| Notable features | satellite galaxy of M31 |
| Other designations | |
|
Andromeda VII, And VII, Cas dSph, PGC 2807155, Cassiopeia Dwarf Galaxy[1][4] |
|
| See also: Galaxy, List of galaxies | |
The Cassiopeia Dwarf (also known as Andromeda VII) is a dwarf spheroidal galaxy about 2.58 Mly away in the constellation Cassiopeia. The Cassiopeia Dwarf is part of the Local group of galaxies and a satellite galaxy of the Andromeda Galaxy (M31).
The Cassiopeia Dwarf was found in 1998, together with the Pegasus Dwarf, by a team of astronomers (Karachentsev and Karachentseva)[5] in Russia and the Ukraine. The Cassiopeia Dwarf and the Pegasus Dwarf are farther from M31 than its other known companion galaxies, yet still appear bound to it by gravity. Neither galaxy contains any young, massive stars or shows traces of recent star formation. Instead, both seem dominated by very old stars, with ages of up to 10 billion years.