Satellite galaxies of the Milky Way

Source: Wikipedia, the free encyclopedia.

The Milky Way has several smaller galaxies gravitationally bound to it, as part of the Milky Way subgroup, which is part of the local galaxy cluster, the Local Group.[1]

There are 61 small galaxies confirmed to be within 420

Sagittarius Dwarf Elliptical Galaxy, which has a diameter of 2.6 kiloparsecs (8,500 ly)[4]
or roughly a twentieth that of the Milky Way.

Characteristics

Satellite galaxies that orbit from 1,000 

disc of the Milky Way Galaxy to the edge of the dark matter halo of the Milky Way at 980,000 ly (300 kpc) from the center of the galaxy,[a] 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.[5][6]

List

The Milky Way's satellite galaxies include the following:[7][2]

Name Diameter (kpc) Distance
(kpc) 		Absolute visual magnitude Type Discovered
Large Magellanic Cloud 4 48.5 −18.1 SBm prehistoric
Antlia 2
 2.9 130 −8.5 Irr? 2018
Sagittarius Dwarf
 2.6 20 −13.5 E 1994
Crater II
 2.2 117.5 −8.2 dSph 2016 [8]
Small Magellanic Cloud 2 61 −16.8 Irr prehistoric
Canes Venatici I
 1.1 220 −8.6 dSph 2006
Canis Major Dwarf
 1.5 8 −14.4 Irr 2003
Boötes III
 1.0 46 −5.75 dSph? 2009
Sculptor Dwarf 0.8 90 −11.1 dE3 1937
Draco Dwarf 0.7 80 −8.8 dE0 1954
Hercules 0.7 135 −6.6 dSph 2006
Leo II 0.7 210 −9.8 dE0 1950
Fornax Dwarf 0.6 140 −13.4 dE2 1938
Eridanus II[9] 0.55 366 −7.1 dSph 2015 [10][11]
Sextans Dwarf Spheroidal 0.5 90 −9.3 dE3 1990
Carina Dwarf Spheroidal 0.5 100 −9.1 dE3 1977
Leo I 0.5 250 −12.0 dE3 1950
Ursa Minor Dwarf 0.4 60 −8.8 dE4 1954
Leo T
 0.34 420 −8.0 dSph/dIrr 2006
Aquarius II 0.32 108 −4.2 dSph 2016 [12]
Boötes I
 0.30 60 −6.3 dSph 2006
Canes Venatici II
 0.30 155 −4.9 dSph 2006
Leo IV 0.30 160 −5.8 dSph 2006
Tucana IV 0.25 48 −3.5 dSph 2015 [13]
Columba I 0.21 182 −4.5 dSph 2015 [13]
Ursa Major II Dwarf 0.20 30 −4.25 dG D 2006
Grus II 0.19 53 −3.9 dSph 2015 [13]
Cetus III 0.18 251 −2.4 dSph? 2017 [14]
Coma Berenices 0.14 42 −4.1 dSph 2006
Hydra II 0.14 128 −4.8 dSph 2015 [15]
Reticulum III 0.13 92 −3.3 dSph 2015 [13]
Pisces II
 0.12 180 −5.0 dSph 2010
Pegasus III 0.11 215 −3.4 dSph 2015 [16][17]
Hydrus I 0.10 28 −4.7 dSph 2018 [18]
Boötes II
 0.10 42 −2.7 dSph 2007
Tucana III 0.09 25 −2.4 dSph 2015 [13]
Virgo I 0.09 91 −0.3 dSph? 2016 [14]
Horologium II 0.09 78 −2.6 dSph 2015 [19]
Sagittarius II 0.08 67 −5.2 dSph 2015 [20]
Leo V 0.08 180 −5.2 dSph 2007
Triangulum II 0.07 30 −1.8 dSph 2015
Segue 2
 0.07 35 −2.5 dSph 2007
Segue 1 0.06 23 −1.5 dSph 2007
Draco II 0.04 20 −2.9 dSph 2015 [20]
Tucana V 0.03 55 −1.6 dSph 2015 [13]
Cetus II 0.03 30 0.0 dSph? 2015 [13]
Reticulum II
 0.064 30 −3.6 dSph 2015 [10][11]
Tucana II 0.33 70 −3.9 dSph 2015 [10][11]
Pisces Overdensity 1.5 80 −13 dSph? 2009
DES 1 0.02 82 −3.05 GC 2016 [21]
Eridanus III 0.028 90 −2.4 dSph?[b] 2015 [10][11]
Horologium I 0.06 100 −3.5 dSph?[b] 2015 [10][11]
Kim 2/Indus I 0.074 100 −3.5 GC 2015 [10][11]
Phoenix II 0.0521 100 −3.7 dSph?[b] 2015 [10][11]
Ursa Major I Dwarf 0.64 100 −5.5 dG D 2005
Pictoris I 0.058 115 −3.7 dSph?[b] 2015 [10][11]
Grus I 0.12 120 −3.4 dSph 2015 [10]
Pegasus IV 0.082 90 −4.25 dSph 2022 [22]
Carina II 0.182 36 −4.5 dSph 2018 [23]
Carina III 0.06 28 −2.4 GC? 2018 [23]
Boötes IV 0.28 209 −4.53 dSph 2019 [24]
Centaurus I 0.076 116 −5.55 dSph 2020 [25]
Pictor II 0.046 46 −3.2 dSph 2016 [26]
Willman 1 0.02 38 −2.53 dSph 2018 [27]
Ursa Major III 0.003 10 +2.2 dSph 2023

Map with clickable regions

Milky WaySagittarius Dwarf Elliptical GalaxySextans DwarfLarge Magellanic CloudSmall Magellanic CloudSculptor DwarfFornax DwarfCarina DwarfBootes DwarfUrsa Major IIUrsa Major IUrsa Minor DwarfDraco Dwarf
Milky Way's satellite galaxies (clickable map)

Streams

See also: List of stellar 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

Notes

  1. ^ The distance to edge of the dark matter halo of the galaxy from its center is the virial radius of a galaxy, Rvir
  2. ^ a b c d May be a globular cluster instead

References

  1. S2CID 118390693
    .
  2. ^
    S2CID 208857848
    .
  3. ^ "Press release: Magellanic Clouds May Be Just Passing Through". Harvard University. January 9, 2007.
  4. doi:10.1086/382905
    .
  5. ^ "Milky Way Ransacks Nearby Dwarf Galaxies". SpaceDaily. 17 October 2014.
  6. ^ "Milky Way ransacks nearby dwarf galaxies". ScienceDaily. 15 October 2014.
  7. ^ Sjölander, Nils. "Milky Way satellite galaxies". Archived from the original on 2014-02-19.
  8. doi:10.1093/mnras/stw733
    .
  9. S2CID 2202492
    .
  10. ^
    S2CID 118267222
    .
  11. ^
    S2CID 12011753
    .
  12. doi:10.1093/mnras/stw2051
    .
  13. ^
    S2CID 55909299
    .
  14. ^
    doi:10.1093/pasj/psx050
    .
  15. S2CID 7814048
    .
  16. S2CID 119302178
    .
  17. S2CID 73677994
    .
  18. ISSN 0035-8711
    .
  19. S2CID 117190468
    .
  20. ^
    S2CID 54042426
    .
  21. doi:10.1093/mnras/stw302
    .
  22. S2CID 247597301
    .
  23. ^
    doi:10.1093/mnras/sty170
    .
  24. doi:10.1093/pasj/psz076
    .
  25. S2CID 208857609
    .
  26. S2CID 56071154
    .
  27. S2CID 118978019
    .

Further reading
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