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]
^
abcMcConnachie, 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.
S2CID16950090.
^
abCollins, 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.
S2CID67749084.