Kumpulan Tempatan
Kumpulan Tempatan ialah sebuah kumpulan galaksi yang termasuk galaksi kita, Bima Sakti. Kumpulan ini terdiri daripada lebih 35 galaksi, dengan pusat graviti terletak di antara Bima Sakti dan Galaksi Andromeda. Galaksi Kumpulan Tempatan meliputi diameter 10 juta tahun cahaya (lihat 1 E+22 m untuk perbandingan jarak) dan mempunyai bentuk binari (dumbel)[1]. Kumpulan ini dianggarkan mepunyai jisim (1.29 ± 0.14)×1012M☉.[1]Kumpulan itu merupakan salah satu kumpulan dalam Gugusan Besar Virgo (atau Gugusan Besar Tempatan).[2]
Dua ahli yang terbesar ialah Bima Sakti dan Galaksi Andromeda. Kedua-dua galaksi pilin berpalang ini mengandungi sistem galaksi satelit tersendiri.
- Sistem satelit Bima Sakti terdiri daripada Galaksi Sagittarius Kerdil, Large Magellanic Cloud, Small Magellanic Cloud, Canis Major Kerdil, Ursa Minor Kerdil, Draco Kerdil, Carina Kerdil, Sextans Kerdil, Sculptor Kerdil, Fornax Kerdil, Leo I, Leo II, and Ursa Major Kerdil.
- Sistem satelit Andromeda terdiri daripada M32, M110, NGC 147, NGC 185, And I, And II, And III, And IV, And V, Pegasus dSph, Cassiopeia Kerdil, And VIII, And IX, and And X.
- Galaksi Triangulum, galaksi ketiga terbesar dan satu-satunya galaksi pilin biasa dalam Kumpulan Tempatan, boleh jadi merupakan gu galaksi Andromeda tetapi mungkin memiliki Pisces Kerdil sebagai satelit.
Ahli lain kumpulan ini yang terasing secara graviti dari subkumpulan besar di atas termasuklah : IC1613, Phoenix Kerdil, Leo A, Tucana Kerdil, Cetus Kerdil, Pegasus Kerdil Irregular, Wolf-Lundmark-Melotte, Aquarius Kerdil, and Sagittarius Kerdil Irregular.
Sejarah
Edwin Hubble yang adalah orang pertama untuk mengenalkan Kumpulan Tempatan dalam Bab 6 bukunya The Realm of Nebulae (Hubble 1936, pp. 124–151). There he describes it as "a typical small group of nebulae which is isolated in the general field." In that book, he delineated by decreasing luminosity its members to be M31, the Bima Sakti, M33, the Awan Magellan Besar, the Awan Magellan Kecil, M32, NGC 205, NGC 6822, NGC 185, IC 1613 and NGC 147. He also identified IC 10 as a possible Local Group member. In the ~70 years since his work, the number of known Local Group members has increased from his initial twelve to thirty-six as of 2003, by way of the discovery of almost two dozen low-luminosity galaxies.[3]
Galaksi komponen
Peta
Jasad galaksi
| Galaksi pilin | |||
|---|---|---|---|
| nama | jenis | buruj | nota |
| Bima Sakti | SBbc | n/a | Galaksi yang terbesar kedua, dan barangkali berat dalam kumpulan. |
| Galaksi Andromeda (M31, NGC 224) | SA(s)b | Andromeda | Largest member of the group, recently (2006) discovered to also be a barred spiral. May be less massive than the Bima Sakti. |
| Galaksi Triangulum` (M33, NGC 598) | SAc | Triangulum | only ordinary spiral galaksi and possible satelit bagi Galaksi Andromeda? |
| Galaksi elips | |||
| name | type | buruj | notes |
| M110 (NGC 205) | E6p | Andromeda | satelit bagi Galaksi Andromeda |
| M32 (NGC 221) | E2 | Andromeda | satelit bagi Galaksi Andromeda |
| Galaksi tak nalar | |||
| name | type | buruj | notes |
| Wolf-Lundmark-Melotte (WLM, DDO 221) | Ir+ | Cetus | |
| IC 10 | KBm or Ir+ | Cassiopeia | |
| Awan Magellan Kecil (SMC, NGC 292) | SB(s)m pec | Tucana | satelit Bima Sakti |
| Canis Major Kerdil | Irr | Canis Major | satelit Bima Sakti |
| Pisces Kerdil (LGS3) | Irr | Pisces | satelit bagi Galaksi Triangulum`? |
| IC 1613 (UGC 668) | IAB(s)m V | Cetus | |
| Phoenix Kerdil | Irr | Phoenix | |
| Large Magellanic Cloud (LMC) | Irr/SB(s)m | Dorado | satelit Bima Sakti |
| Leo A (Leo III) | IBm V | Leo | |
| Sextans B (UGC 5373) | Ir+IV-V | Sextans | |
| NGC 3109 | Ir+IV-V | Hydra | |
| Sextans A (UGCA 205) | Ir+V | Sextans | |
| Galaksi elips kerdil | |||
| name | type | buruj | notes |
| NGC 147 (DDO 3) | dE5 pec | Cassiopeia | satelit bagi Galaksi Andromeda |
| SagDIG (Sagittarius Kerdil Irregular Galaxy) | IB(s)m V | Sagittarius | Most remote from barycenter member thought to be in the Local Group.[4] |
| NGC 6822 (Barnard's Galaxy) | IB(s)m IV-V | Sagittarius | |
| Pegasus Kerdil (Pegasus Kerdil Irregular, DDO 216) | Irr | Pegasus | |
| Galaksi sferoid kerdil | |||
| name | type | buruj | notes |
| Boötes Kerdil | dSph | Boötes | |
| Cetus Kerdil | dSph/E4 | Cetus | |
| Canes Venatici Kerdil | dSph | Canes Venatici | |
| Andromeda III | dE2 | Andromeda | satelit bagi Galaksi Andromeda |
| NGC 185 | dE3 pec | Cassiopeia | satelit bagi Galaksi Andromeda |
| Andromeda I | dE3 pec | Andromeda | satelit bagi Galaksi Andromeda |
| Sculptor Kerdil (E351-G30) | dE3 | Sculptor | satelit Bima Sakti |
| Andromeda V | dSph | Andromeda | satelit bagi Galaksi Andromeda |
| Andromeda II | dE0 | Andromeda | satelit bagi Galaksi Andromeda |
| Fornax Kerdil (E356-G04) | dSph/E2 | Fornax | satelit Bima Sakti |
| Carina Kerdil (E206-G220) | dE3 | Carina | satelit Bima Sakti |
| Antlia Kerdil | dE3 | Antlia | |
| Leo I (DDO 74) | dE3 | Leo | satelit Bima Sakti |
| Sextans Kerdil | dE3 | Sextans | satelit Bima Sakti |
| Leo II (Leo B) | dE0 pec | Leo | satelit Bima Sakti |
| Ursa Minor Kerdil | dE4 | Ursa Minor | satelit Bima Sakti |
| Draco Kerdil (DDO 208) | dE0 pec | Draco | satelit Bima Sakti |
| SagDEG (Sagittarius Kerdil Elliptical Galaxy) | dSph/E7 | Sagittarius | satelit Bima Sakti |
| Tucana Kerdil | dE5 | Tucana | |
| Cassiopeia Kerdil (Andromeda VII) | dSph | Cassiopeia | satelit bagi Galaksi Andromeda |
| Pegasus Kerdil Spheroidal Galaxy (And VI) | dSph | Pegasus | satelit bagi Galaksi Andromeda |
| Ursa Major Kerdil | dSph | Ursa Major | satelit Bima Sakti |
| Pengecaman tidak jelas | |||
| name | type | buruj | notes |
| Virgo Stellar Stream | dSph (remnant)? | Virgo | In the process of merging with the Bima Sakti |
| Willman 1 | kerdil Spherical galaksi or Globular gugusan? | Ursa Major | 147,000 light-years away |
| Andromeda IV | Irr? | Andromeda | kemungkinan bukannya galaksi |
| UGC-A 86 (0355+66) | Irr, dE or S0 | Camelopardalis | |
| UGC-A 92 (EGB0427+63) | Irr or S0 | Camelopardalis | |
| Kemungkinan bukan-ahli | |||
| nama | jenis | buruj | nota |
| GR 8 (DDO 155) | Im V | Virgo | |
| IC 5152 | IAB(s)m IV | Indus | |
| NGC 55 | SB(s)m | Sculptor | |
| Aquarius Kerdil (DDO 210) | Im V | Aquarius | |
| NGC 404 | E0 or SA(s)0- | Andromeda | |
| NGC 1569 | Irp+ III-IV | Camelopardalis | |
| NGC 1560 (IC 2062) | Sd | Camelopardalis | |
| Camelopardalis A | Irr | Camelopardalis | |
| Argo Kerdil | Irr | Carina | |
| 2318-42 | Irr | Grus | |
| UKS 2323-326 | Irr | Sculptor | |
| UGC 9128 (DDO 187) | Irp+ | Boötes | |
| Palomar 12 (Capricornus Kerdil) | Capricornus | ||
| Palomar 4 (asalnya dipanggil Ursa Major Kerdil) | Ursa Major | a globular gugusan formerly classified as a kerdil spheroidal galaksi | |
| Sextans C | |||
Objek ketara yang lain
Lihat juga
- Kumpulan dan gugusan galaksi
- Senarai galaksi terdekat
- Senarai gugusan galaksi
- Gugusan Besar Tempatan
- Galaksi satelit Andromeda
- Galaksi satelit Bima Sakti
Rujukan
Pautan luar
- The Local Group of Galaxies, SEDS Messier pages
- A Survey of the Resolved Stellar Content of Nearby Galaxies Currently Forming Stars Diarkibkan 2009-05-09 di Wayback Machine, Lowell Observatory
- van den Bergh, Sidney (2000). "Updated Information on the Local Group". The Publications of the Astronomical Society of the Pacific. 112 (770): 529–536. doi:10.1086/316548.