(M31, Messier 31, NGC 224)
(spiral galaxy in the Local Group)
Andromeda (M31 or Messier 31, NGC 224)
is a spiral galaxy about
two and a half million light-years away.
It is within the Local Group and is the nearest galaxy
to the Milky Way that is similar: the Local Group contains
one more somewhat similar spiral galaxy that is substantially smaller,
and numerous smaller dwarf satellite galaxies.
Andromeda is somewhat larger than the Milky Way, with
on the order of a trillion stars.
Andromeda was observed before the current concept of a galaxy
was established, at the time, known as the Great Andromeda Nebula.
Some of the satellite galaxies of Andromeda are
known as Andromeda I (or And I), Andromeda II, etc.
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|Prefix||Example|| || |
|And||And I||M31 satellites|| |
|Andromeda||Andromeda I||M31 satellites|| |
Referenced by pages:
astronomical unit (AU)
Bologna Catalog of Globular Clusters (Bol)
Chandra X-ray Observatory (CXO)
galaxy main sequence
hierarchical assembly of galaxies
luminous blue variable (LBV)
Large Magellanic Cloud (LMC)
Local Group (LG)
Triangulum Galaxy (M33)
Messier Catalog (M)
Principal Galaxies Catalog (PGC)
rare designator prefixes
satellite plane problem