Product Code Database
The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly , and a total mass of the order of .The mass of the Local Group is essentially accounted for by the mass of the Milky Way and the Andromeda Galaxy. Estimates for the mass of each galaxy are compatible with , and Peñarrubia et al. (2014) estimate for the Local Group, but Karachentsev and Kashibadze (2006) estimate the somewhat lower value of . It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about and are moving toward one another with a velocity of . The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.
The two largest members, the Andromeda and the Milky Way galaxies, are both spiral galaxies with masses of about solar masses each. Each has its own system of satellite galaxies:
The Triangulum Galaxy (M33) is the third-largest member of the Local Group, with a mass of approximately , and is the third spiral galaxy. It is unclear whether the Triangulum Galaxy is a companion of the Andromeda Galaxy; the two galaxies are 750,000 light years apart, and experienced a close passage 2–4 billion years ago which triggered star formation across Andromeda's disk. The Pisces Dwarf Galaxy is equidistant from the Andromeda Galaxy and the Triangulum Galaxy, so it may be a satellite of either.
The other members of the group are likely gravitationally secluded from these large subgroups: IC 10, IC 1613, Phoenix Dwarf Galaxy, Leo A, Tucana Dwarf Galaxy, Cetus Dwarf Galaxy, Pegasus Dwarf Irregular Galaxy, Wolf–Lundmark–Melotte, Aquarius Dwarf Galaxy, and Sagittarius Dwarf Irregular Galaxy.
The membership of NGC 3109, with its companions Sextans A and the Antlia Dwarf Galaxy as well as Sextans B, Leo P, Antlia B and possibly Leo A, is uncertain due to extreme distances from the center of the Local Group. The Antlia-Sextans Group is unlikely to be gravitationally bound to the Local Group due to probably lying outside the Local Group's zero-velocity surface—which would make it a true galaxy group of its own rather than a subgroup within the Local Group. This possible independence may, however, disappear as the Milky Way continues coalescing with Andromeda due to the increased mass, and density thereof, plausibly widening the radius of the zero-velocity surface of the Local Group.
rect 392 53 405 72 Light-year
circle 318 239 20 Milky Way rect 345 256 375 284 Milky Way
circle 383 310 5 NGC 6822 rect 348 292 380 322 NGC 6822
circle 177 27 10 Sextans B rect 155 17 215 35 Sextans B circle 130 37 10 Sextans A rect 95 25 155 45 Sextans A
circle 100 144 5 NGC 3109 rect 65 130 100 160 NGC 3109 circle 109 149 5 Antlia Dwarf rect 109 146 145 175 Antlia Dwarf
circle 314 119 5 Leo A rect 280 97 340 125 Leo A circle 315 210 5 Leo I (dwarf galaxy) rect 280 180 315 205 Leo I (dwarf galaxy) rect 320 180 335 220 Leo II (dwarf galaxy) circle 349 213 5 Canes Dwarf rect 350 195 400 223 Canes Dwarf
circle 310 350 15 Phoenix Dwarf rect 275 325 335 375 Phoenix Dwarf circle 265 415 15 Tucana Dwarf rect 215 395 275 445 Tucana Dwarf
circle 392 445 5 Wolf-Lundmark-Melotte rect 360 435 392 455 Wolf-Lundmark-Melotte circle 370 410 5 Cetus Dwarf rect 345 395 390 430 Cetus Dwarf circle 395 373 10 IC 1613 rect 390 373 420 400 IC 1613 rect 381 335 393 357 SagDIG rect 430 450 480 475 SagDIG rect 393 335 406 356 Aquarius Dwarf rect 450 425 510 450 Aquarius Dwarf circle 412 332 12 LGS 3 rect 465 405 510 425 LGS 3
circle 460 361 21 Pegasus Dwarf rect 485 370 540 405 Pegasus Dwarf
poly 440 282 455 260 511 259 493 285 Andromeda Galaxy rect 484 280 550 305 Andromeda Galaxy
circle 417 304 2 Triangulum Galaxy rect 400 321 480 340 Triangulum Galaxy
circle 417 254 15 NGC 185 rect 440 185 480 211 NGC 185 rect 432 237 447 260 NGC 147 rect 480 195 508 225 NGC 147 poly 450 264 434 265 431 280 442 280 M110 rect 508 205 540 225 M110 circle 461 229 17 IC 10 rect 493 241 525 256 IC 10
rect 524 305 550 323 M32
circle 394 272 14 Andromeda II rect 500 345 515 360 Andromeda II rect 427 279 438 294 Andromeda III rect 518 345 530 360 Andromeda III rect 438 282 450 294 Andromeda I rect 557 345 570 360 Andromeda I
| + Properties of galactic bodies in and around the Local Group | |||
| Andromeda Galaxy (M31, NGC 224) | SAb | Andromeda | Largest galaxy in the group Diameter (D25 isophote): 152,000 light-years Mass: Number of stars: ca. . |
| Milky Way Galaxy | SBbc | Sagittarius (centre) | Second largest galaxy in the group, which may or may not be the most massive galaxy of the group. Diameter (D25 isophote): 87,400 light-years Mass: Number of stars: . |
| Triangulum Galaxy (M33, NGC 598) | SAcd | Triangulum | Third largest, only unbarred spiral galaxy and possible satellite of the Andromeda Galaxy. Diameter (D25 isophote): 60,000 light-years Mass: Number of stars: . |
| Large Magellanic Cloud (LMC, Dorado Dwarf) | Irr/SB(s)m | Dorado | Fourth largest member of the group, satellite of Milky Way and only Magellanic Spiral Galaxy in the local group Mass: Diameter (D25 isophote): 32,200 light-years |
| NGC 3109 (Antlia Sextans galaxy l) | SB(s)m | Hydra | Member of Antlia-Sextans Group |
| M32 (NGC 221, Andromeda Dwarf) | cE2 | Andromeda | Satellite of the Andromeda Galaxy, shows signs of a supermassive black hole |
| Wolf–Lundmark–Melotte (WLM, DDO 221) | Ir+ | Cetus | Possible size between Small Magellanic Cloud and Large Magellanic Cloud |
| IC 10 (Cascopea IV, PGC 4774942-40+4) | KBm or Ir+ | Cassiopeia | Only known starbust galaxy in the Local Group |
| Small Magellanic Cloud (SMC, NGC 292, Tucana galaxy) | SB(s)m pec | Tucana | Satellite of Milky Way, 6th largest galaxy in the local group mass: 7 billion |
| Pisces Dwarf (LGS3,Pisces I dwarf irregular) | Irr | Pisces | Possible satellite of the Triangulum Galaxy |
| IC 1613 (UGC 668, UGCA 47954) | IAB(s)m V | Cetus | |
| Phoenix Dwarf (Phoenix I dwarf) | Irr | Phoenix | |
| Leo A (Leo III, PCA QA JO74974) | IBm V | Leo | |
| Aquarius Dwarf (DDO 210, Aquarius I, ESO 497-4054.4591 G) | IB(s)m | Aquarius | Distance 3.2 million light years. Quite isolated in space, membership to Local Group established in 1999. |
| SagDIG (Sagittarius Dwarf Irregular Galaxy, Sagittarius II) | IB(s)m V | Sagittarius | Most remote from barycenter member thought to be in the Local Group. |
| NGC 6822 (Barnard's Galaxy, AO 4797) | IB(s)m IV-V | Sagittarius | |
| Pegasus Dwarf (Pegasus Dwarf Irregular, DDO 216) | Irr | Pegasus | |
| UGC 4879 (VV124) | IAm | Ursa Major | One of the most isolated galaxies in Local Group. Situated at the edge of the Local Group. |
| Sextans A (UGCA 205, AO 4977) | Ir+V | Sextans | Member of Antlia-Sextans Group |
| Sextans B (UGC 5373, QRT 947748) | Ir+IV-V | Sextans | Member of Antlia-Sextans Group |
| Leo P (AGC 19470059) | Irr | Leo | Member of Antlia-Sextans Group, extraordinarily low metallicity (Z = 0.03ZMW) |
| AGC 198606 (Leo VI) | Irr? | Leo | Gas-rich ultra-faint dwarf galaxy |
| AGC 215417(Leo VII) | Irr? | Leo | Gas-rich ultra-faint dwarf galaxy |
| AGC 219656 | Irr? | Leo | Gas-rich ultra-faint dwarf galaxy |
| AGC 249525 | Irr? | Boötes | Gas-rich ultra-faint dwarf galaxy, Situated at the edge of the Local Group |
| AGC 268069 | Irr? | Serpens | Gas-rich ultra-faint dwarf galaxy |
| M110 (NGC 205) | dE6p | Andromeda | Satellite of the Andromeda Galaxy and 5th largest galaxy with the mass of 9.3 billion solar masses. |
| NGC 147 (DDO 3) | dE5 pec | Cassiopeia | Satellite of the Andromeda Galaxy |
| Boötes I (DDO 9774998.074÷×47) | dSph | Boötes | satellite of the Milky Way |
| Cetus Dwarf | dSph/E4 | Cetus | 3.4 million light-years away size:999 light-years |
| Canes Venatici I Dwarf and Canes Venatici II Dwarf | dSph | Canes Venatici | Satellites of the Milky Way |
| Andromeda III | dE2 | Andromeda | Satellite of the Andromeda Galaxy |
| NGC 185 | dE3 pec | Cassiopeia | Satellite of the Andromeda Galaxy |
| Andromeda I | dE3 pec | Andromeda | Satellite of the Andromeda Galaxy |
| Sculptor Dwarf (E351-G30) | dE3 | Sculptor | Satellite of Milky Way |
| Andromeda V (UKS 4977-94) | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda II (NCA 14) | dE0 | Andromeda | Satellite of the Andromeda Galaxy |
| Fornax Dwarf (E356-G04) | dSph/E2 | Fornax | Satellite of Milky Way |
| Carina Dwarf (E206-G220) | dE3 | Carina | Satellite of Milky Way |
| Leo I (DDO 74) | dE3 | Leo | Satellite of Milky Way |
| Sextans Dwarf (Sextans 1) | dE3 | Sextans | Satellite of Milky Way |
| Leo II (Leo B) | dE0 pec | Leo | Satellite of Milky Way |
| Ursa Minor Dwarf (NCA 47-49) | dE4 | Ursa Minor | Satellite of Milky Way |
| Draco Dwarf (DDO 208) | dE0 pec | Draco | Satellite of Milky Way |
| SagDSG (Sagittarius Dwarf Spheroidal Galaxy) | dSph/E7 | Sagittarius | Satellite of Milky Way |
| Tucana Dwarf | dE5 | Tucana | 3.2 million ly away |
| Cassiopeia Dwarf (Andromeda VII, NCA 4) | dSph | Cassiopeia | Satellite of the Andromeda Galaxy |
| Pegasus Dwarf Spheroidal Galaxy (Andromeda VI) | dSph | Pegasus | Satellite of the Andromeda Galaxy |
| Ursa Major I Dwarf | dSph | Ursa Major | Satellite of the Milky Way |
| Ursa Major II Dwarf | dSph | Ursa Major | Satellite of the Milky Way |
| Ursa Major III | dSph | Ursa Major | Satellite of the Milky Way |
| Leo IV | dSph | Leo | Satellite of the Milky Way |
| Leo V | dSph | Leo | Satellite of the Milky Way |
| Leo T | dSph/Irr | Leo | Satellite of the Milky Way |
| Boötes II | dSph | Boötes | Satellite of the Milky Way |
| Boötes III (NCA 4.9) | dSph | Boötes | Satellite of the Milky Way, Bootes lll likely formed both the Bootes Ill Stream & the Monosoros Stellar stream |
| Boötes IV | dSph | Boötes | Satellite of the Milky Way |
| Coma Berenices | dSph | Coma Berenices | Satellite of the Milky Way |
| Segue 2 (Aries Dwarf, NCA 429) | dSph | Aries | Satellite of the Milky Way size:220 light-years number of stars:≈1000 |
| Hercules (NCA 4977429) | dSph | Hercules | Satellite of the Milky Way |
| Pisces II | dSph | Pisces | Satellite of the Milky Way |
| Reticulum II | dSph | Reticulum | Satellite of the Milky Way |
| Reticulum III | dSph | Reticulum | Satellite of the Milky Way |
| Eridanus II | dSph | Eridanus | Probable satellite of the Milky Way |
| Grus I | dSph | Grus | Satellite of the Milky Way |
| Grus II | dSph | Grus | Satellite of the Milky Way |
| Tucana II | dSph | Tucana | Satellite of the Milky Way |
| Hydrus I (Hydrus Dwarf spheroidal galaxy) | dSph | Hydrus | Satellite of the Milky Way |
| Draco II | dSph | Draco | Satellite of the Milky Way |
| Carina III | dSph | Carina | Satellite of the Milky Way |
| Triangulum II (Laevens 2) | dSph | Triangulum | Satellite of the Milky Way |
| Carina II | dSph | Carina | Satellite of the Milky Way |
| Pictor II | dSph | Pictor | Satellite of the Milky Way |
| Horologium II | dSph | Horologium | Satellite of the Milky Way |
| Virgo I | dSph | Virgo | Satellite of the Milky Way |
| Virgo III | dSph? | Virgo | Satellite of the Milky Way |
| Sextans II | dSph? | Sextans | Satellite of the Milky Way |
| Aquarius II | dSph | Aquarius | Satellite of the Milky Way |
| Aquarius III | dSph? | Aquarius | Satellite of the Milky Way |
| Crater II | dSph | Crater | Satellite of the Milky Way |
| Hydra II | dSph | Hydra | Satellite of the Milky Way |
| Antlia II | dSph | Antlia | Satellite of the Milky Way |
| Pegasus III | dSph | Pegasus | Satellite of the Milky Way |
| Pegasus IV | dSph | Pegasus | Satellite of the Milky Way |
| Pegasus W | dSph | Pegasus | Recent star formation, could still be starforming |
| Cetus III | dSph | Cetus | Satellite of the Milky Way |
| Leo K | dSph? | Leo | Satellite of the Milky Way |
| Leo M | dSph? | Leo | Satellite of the Milky Way |
| Leo VI | dSph | Leo | Satellite of the Milky Way |
| Leo Minor I | dSph? | Leo Minor | Satellite of the Milky Way |
| Boötes V | dSph? | Boötes | Satellite of the Milky Way |
| Virgo II | dSph? | Virgo | Satellite of the Milky Way |
| Tucana B | dSph | Tucana | |
| DES 1 | dE | Perseus | Satellite of Milky Way |
| Antlia Dwarf | dE3/dSph/Irr? | Antlia | Member of Antlia-Sextans Group |
| Andromeda IX | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda X | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XI | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XII | dSph | Andromeda | Possible satellite of the Andromeda Galaxy |
| Andromeda XIII (Pisces III) | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XIV (Pisces IV) | dSph | Pisces | Possible satellite of the Andromeda Galaxy |
| Andromeda XV | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XVII | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XIX | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XX | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XXI | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XXII | dSph | Pisces | Possible satellite of the Triangulum Galaxy |
| Andromeda XXIII | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XXIV | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XXV | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XXVI | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XXVII | dSph | Andromeda | Satellite of the Andromeda Galaxy, tidally disrupted |
| Andromeda XXIX | dSph | Pegasus | Satellite of the Andromeda Galaxy |
| Andromeda XXX (Cassiopeia II) | dSph? | Cassiopeia | Satellite of the Andromeda Galaxy |
| Andromeda XXXI (Lacerta I) | dSph? | Lacerta | Satellite of the Andromeda Galaxy |
| Andromeda XXXII (Cassiopeia III) | dSph? | Cassiopeia | Satellite of the Andromeda Galaxy |
| Andromeda XXXIV (Pegasus V) | dSph | Pegasus | Satellite of the Andromeda Galaxy |
| Andromeda XXXV | dSph | Andromeda | Satellite of the Andromeda Galaxy |
| Andromeda XVI (Pisces V) | dSph | Pisces | Possible satellite of the Andromeda Galaxy |
| Andromeda XXVIII | dSph? | Pegasus | Possible satellite of the Andromeda Galaxy |
| Andromeda XXXIII (Perseus I) | dSph? | Perseus | Possible satellite of the Andromeda Galaxy |
| Andromeda XVIII | dSph | Andromeda | |
| Centaurus I | dSph | Centaurus | Satellite of the Milky Way |
| Pisces VII (Triangulum III) | dSph? | Pisces | Candidate, possible satellite of the Triangulum Galaxy |
| Virgo Stellar Stream | dSph (remnant)? | Virgo | In the process of merging with the Milky Way |
| Canis Major Dwarf | Irr? | Canis Major | Possibly a dwarf galaxy in the process of merging with the Milky Way |
| Hydra 1 | Hydra | Possibly a dwarf galaxy in the process of merging with the Milky Way | |
| Tucana III | dSph or cluster? | Tucana | Satellite of the Milky Way, tidally disrupting |
| Tucana IV | dSph or cluster? | Tucana | Satellite of the Milky Way |
| Tucana V | dSph or cluster? | Tucana | Possibly non-existent |
| Columba I | dSph or cluster? | Columba | Satellite of the Milky Way |
| Segue 1 | dSph or Globular Cluster | Leo | Satellite of the Milky Way |
| Cetus II | Cetus | Likely part of Sagittarius tidal stream | |
| Willman 1 | dSph or Globular Cluster | Ursa Major | 147,000 light-years away |
| Horologium I | dSph or Globular Cluster | Horologium | Satellite of the Milky Way. Not to be confused with the Horologium Supercluster. |
| Pictoris | dSph or Globular Cluster | Pictor | Satellite of the Milky Way |
| Phoenix II | dSph or Globular Cluster | Phoenix | Satellite of the Milky Way |
| Indus I (Kim 2, Indus Dwarf) | dSph or Globular Cluster | Indus | Satellite of the Milky Way |
| Eridanus III | dSph or Globular Cluster | Eridanus | Satellite of the Milky Way or SMC |
| Sagittarius II | dSph or Globular Cluster | Sagittarius | Satellite of the Milky Way |
| Andromeda VIII (Adsant-40-7 quote serp galaxy) | dSph? | Andromeda | Satellite of the Andromeda Galaxy, tidally disrupting |
| Antlia B | Antlia | Member of Antlia-Sextans Group | |
| Andromeda IV | Irr | Andromeda | Once considered to be associated with M31. Its distance is now known to be 22 to 24 million light years (not close to the Andromeda Galaxy at all). |
| GR 8 (DDO 155) | Im V | Virgo | Distance 7.9 million light years |
| IC 5152 (Indus III) | IAB(s)m IV | Indus | Distance 5.8 million light years, possibly an outlying member of the Local Group |
| KK 153 | Ursa Major | Distance 6.5 million light years, possibly an outlying member of the Local Group | |
| NGC 300 | SA(s)d | Sculptor | Distance 6.07 million light years |
| NGC 55 | SB(s)m | Sculptor | Distance 6.5 million light years |
| NGC 404 | E0 or SA(s)0− | Andromeda | Distance 10 million light years |
| NGC 1569 (IC 49447) | Irp+ III-IV | Camelopardalis | In IC 342 group of galaxies. Distance 11 million light years |
| NGC 1560 (IC 2062) | Sd | Camelopardalis | Distance 8-12 million light years |
| Camelopardalis A | Irr | Camelopardalis | Distance 12 million light years |
| Argo Dwarf | Irr | Carina | 7.1 million light-years away |
| ESO 347-8 (2318–42, PGC 475744) | Irr | Grus | 9 million light-years away fairly isolated until million light years. away from the galaxy |
| UKS 2323-326 (ESO 407-18) | Irr | Sculptor | Distance 7.2 million light-years |
| UGC 9128 (DDO 187) | Irp+ | Boötes | 7 million light-years away |
| KKs 3 (Hydrus II) | dSph | Hydrus | Distance 5.2 million light-years |
| Palomar 12 (Capricornus Dwarf) | dSphr | Capricornus | Globular cluster formerly classified as a dwarf spheroidal galaxy |
| Palomar 4 (Ursa Major Dwarf) | d Sphr | Ursa Major | Globular cluster formerly classified as a dwarf spheroidal galaxy |
| Palomar 5 (Serpens Dwarf) | Serpens | Globular cluster formerly classified as a dwarf spheroidal galaxy | |
| Palomar 3 (Sextans C) | Sculptor | Globular cluster formerly classified as a dwarf spheroidal galaxy | |
| Segue 3 | Pegasus | Globular cluster formerly classified as a dwarf spheroidal galaxy | |
| Laevens 1 (Crater Dwarf) | Crater | Globular cluster formerly classified as a dwarf spheroidal galaxy | |
| DES J2038-4609 (Indus II) | Indus | Likely a chance alignment of stars | |
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