The
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
has several smaller
galaxies gravitationally bound to it, as part of the Milky Way
subgroup
In group theory, a branch of mathematics, a subset of a group G is a subgroup of G if the members of that subset form a group with respect to the group operation in G.
Formally, given a group (mathematics), group under a binary operation  ...
, which is part of the local galaxy cluster, the
Local Group.
There are 61 small galaxies confirmed to be within of the Milky Way,
but not all of them are necessarily in orbit, and some may themselves be in orbit of other satellite galaxies. The only ones visible to the naked eye are the
Large
Large means of great size.
Large may also refer to:
Mathematics
* Arbitrarily large, a phrase in mathematics
* Large cardinal, a property of certain transfinite numbers
* Large category, a category with a proper class of objects and morphisms (o ...
and
Small
Small means of insignificant size
Size in general is the Magnitude (mathematics), magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to three geometrical measures: length, area, or ...
Magellanic Clouds, which have been observed since prehistory. Measurements with the Hubble Space Telescope in 2006 suggest the Magellanic Clouds may be moving too fast to be orbiting the Milky Way. Of the galaxies confirmed to be in orbit, the largest is the
Sagittarius Dwarf Spheroidal Galaxy, which has a diameter of
or roughly a twentieth that of the Milky Way.
Characteristics
Satellite galaxies that orbit from of the edge of the
disc of the Milky Way Galaxy to the edge of the
dark matter halo of the Milky Way at from the center of the galaxy, are generally depleted in hydrogen gas compared to those that orbit more distantly. This is because of their interactions with the dense hot gas halo of the Milky Way that strip cold gas from the satellites. Satellites beyond that region still retain copious quantities of gas.
List
The Milky Way's satellite galaxies include the following:
Map with clickable regions
Image:Satellite_Galaxies.svg, frame, center, Milky Way's satellite galaxies (clickable map)
rect 289 219 352 251 Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
rect 319 252 380 281 Sagittarius Dwarf Elliptical Galaxy
rect 187 81 229 113 Sextans Dwarf
rect 168 273 249 318 Large Magellanic Cloud
rect 229 326 288 368 Small Magellanic Cloud
The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of approximately 7 bill ...
rect 297 376 352 407 Sculptor Dwarf
rect 183 446 234 476 Fornax Dwarf
rect 107 297 150 332 Carina Dwarf
rect 296 107 339 144 Bootes Dwarf
rect 336 180 408 196 Ursa Major II
rect 357 40 423 59 Ursa Major I
rect 370 110 428 142 Ursa Minor Dwarf
rect 430 119 470 154 Draco Dwarf
Streams
The Sagittarius Dwarf Spheroidal Galaxy is currently in the process of being
consumed by the Milky Way and is expected to pass through it within the next 100 million years. The
Sagittarius Stream is a stream of stars in polar orbit around the Milky Way leeched from the Sagittarius Dwarf. The
Virgo Stellar Stream is a stream of stars that is believed to have once been an orbiting dwarf galaxy that has been completely distended by the Milky Way's gravity.
See also
*
List of Andromeda's satellite galaxies
*
List of nearest galaxies
*
Local Group
Notes
References
Further reading
*
{{Portal bar, Physics, Stars, Science
*
Local Group