Andromeda III

Andromeda III is a dwarf spheroidal galaxy about 2.44 million light-years away in the constellation Andromeda. It is part of the Local Group and is a satellite galaxy of the Andromeda Galaxy (M31). The galaxy was discovered by Sidney van den Bergh[2] on photographic plates taken in 1970 and 1971.[3]

Not to be confused with 3 Andromedae.
Andromeda III
Observation data (J2000 epoch)
ConstellationAndromeda
Right ascension 00h 35m 33.8s[1]
Declination+36° 29′ 52″[1]
Redshift−351±9 km/s[1]
Distance2.44 ± 0.08 Mly (748 ± 25 kpc)[2]
Apparent magnitude (V)15.0[1]
Characteristics
TypedSph[1]
Apparent size (V)4′.5 × 3′.0[1]
Notable featuressatellite galaxy of M31
Other designations
AndIII,[1] RC2 Anon 0032+36,[1] PGC 2121[1]

Observations of the dwarf galaxy using the WFPC2 in 2002 indicate that the bulk of the galaxy is around three billion years younger than the general population of globular clusters in our own galaxy. However, there are some older stars that are comparable in age to the Milky Way galactic clusters. There is no evidence for younger stars in this dwarf galaxy, suggesting no star formation is occurring. The dwarf galaxy is located at a distance of around 75 kpc from the center of M31.[4] A total of 56 variable stars have been discovered in And III, including 51 RR Lyrae variables.[5]

See also

References
  1. "NASA/IPAC Extragalactic Database". Results for AndIII. Retrieved 2006-12-18.
  2. McConnachie, A. W.; et al. (2005). "Distances and metallicities for 17 Local Group galaxies". Monthly Notices of the Royal Astronomical Society. 356 (4): 979–997. arXiv:astro-ph/0410489. Bibcode:2005MNRAS.356..979M. doi:10.1111/j.1365-2966.2004.08514.x.
  3. van den Bergh, Sydney (January 1972). "Search for Faint Companions to M31". Astrophysical Journal. 171: L31. Bibcode:1972ApJ...171L..31V. doi:10.1086/180861.
  4. Da Costa, G. S.; et al. (July 2002). "The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda III". The Astronomical Journal. 124 (1): 332–348. arXiv:astro-ph/0204109. Bibcode:2002AJ....124..332D. doi:10.1086/340965.
  5. Pritzl, Barton J.; et al. (May 2005). "The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda I and Andromeda III". The Astronomical Journal. 129 (5): 2232–2256. arXiv:astro-ph/0501083. Bibcode:2005AJ....129.2232P. doi:10.1086/428372.


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