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Andromeda XVIII
DSS image of Andromeda XVIII
Observation data ( J2000 epoch)
Constellation Andromeda
Right ascension00h 02m 14.5s [1]
Declination+45° 05′ 20″ [1]
Heliocentric radial velocity−326.2 ± 2.7 [2]
Distance4,420 ± 290  kly (1,355 ± 88  kpc)
Group or cluster Local Group
Apparent magnitude (V)15.50 ± 0.24 [3]
Absolute magnitude (V)−10.41 ± 0.28 [3]
Characteristics
TypedG [1]
Mass4.2×106 ± 0.3×106 [3]  M
Half-light radius (physical)325 ± 24 [2]
Other designations
PGC 5056918 [4]

Andromeda XVIII, discovered in 2008, is a dwarf spheroidal galaxy (has no rings, low luminosity, much dark matter, little gas or dust), which is a satellite of the Andromeda Galaxy (M31). It is one of the 14 known dwarf galaxies orbiting M31. It was announced in 2010 that the orbiting galaxies lie close to a plane running through M31's center.[ citation needed]

See also

References

  1. ^ a b c McConnachie, Alan W; Huxor, Avon; Martin, Nicolas F; Irwin, Mike J; Chapman, Scott C; Fahlman, Gregory; Ferguson, Annette M. N; Ibata, Rodrigo A; Lewis, Geraint F; Richer, Harvey; Tanvir, Nial R (2008). "A Trio of New Local Group Galaxies with Extreme Properties". The Astrophysical Journal. 688 (2): 1009. arXiv: 0806.3988. Bibcode: 2008ApJ...688.1009M. doi: 10.1086/591313. S2CID  16950090.
  2. ^ a b Collins, Michelle L. M; Chapman, Scott C; Rich, R. Michael; Ibata, Rodrigo A; Martin, Nicolas F; Irwin, Michael J; Bate, Nicholas F; Lewis, Geraint F; Peñarrubia, Jorge; Arimoto, Nobuo; Casey, Caitlin M; Ferguson, Annette M. N; Koch, Andreas; McConnachie, Alan W; Tanvir, Nial (2013). "A Kinematic Study of the Andromeda Dwarf Spheroidal System". The Astrophysical Journal. 768 (2): 172. arXiv: 1302.6590. Bibcode: 2013ApJ...768..172C. doi: 10.1088/0004-637X/768/2/172. S2CID  67749084.
  3. ^ a b c Makarova, L. N; Makarov, D. I; Karachentsev, I. D; Tully, R. B; Rizzi, L (2017). "Star formation history of And XVIII: a dwarf spheroidal galaxy in isolation". Monthly Notices of the Royal Astronomical Society. 464 (2): 2281. arXiv: 1609.09706. Bibcode: 2017MNRAS.464.2281M. doi: 10.1093/mnras/stw2502. S2CID  119275751.
  4. ^ "NAME Andromeda XVIII". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 19 September 2017.