NGC 3109

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NGC 3109
300px
NGC 3109 by GALEX (ultraviolet)
Observation data (J2000 epoch)
Constellation Hydra
Right ascension 10h 03m 06.9s[1]
Declination −26° 09′ 34″[1]
Redshift 403 ± 1 km/s[1]
Distance 4.3 ± 0.3 Mly (1.33 ± 0.08 Mpc)[2][3]
Type SB(s)m[1]
Apparent dimensions (V) 19′.1 × 3′.7[1]
Apparent magnitude (V) 10.4[1]
Other designations
UGCA 194, PGC, 29128,[1] h 3221, GC 2003[4]
See also: Galaxy, List of galaxies

NGC 3109 is a small Magellanic type spiral or irregular galaxy around 4.2 Mly away in the direction of the constellation of Hydra. It is the most prominent member of a Local Group subgroup. NGC 3109 is believed to be tidally interacting with the dwarf elliptical galaxy, Antlia Dwarf.[5] It was discovered by John Herschel on March 24, 1835 while he was in what is now South Africa.[4]

Size and morphology

NGC 3109 is classified as a Magellanic type irregular galaxy,[6] but it may in fact be a small spiral galaxy. If it is a spiral galaxy, it would be the smallest in the Local Group.[7] NGC 3109 has a mass of about 2.3×109 times the mass of the Sun, of which 20% is in the form of neutral hydrogen.[8] It is oriented edge-on from our point of view, and may contain a disk and a halo.[7] The disk appears to be composed of stars of all ages, whereas the halo contains only very old and metal-poor stars.[9] NGC 3109 does not appear to possess a galactic nucleus.[8]

From measurements of the neutral atomic hydrogen in the galaxy, it has been found that the disk of NGC 3109 is warped. The warp has the same radial velocity as gas in the Antlia Dwarf galaxy, indicating that the two galaxies had a close encounter approximately one billion years ago.[10]

Composition

Based on spectroscopy of red giants in NGC 3109, it is known that the galaxy has a low metallicity, similar to that to the Small Magellanic Cloud.[11] It is one of the most metal-poor galaxies in the Local group.[12] NGC 3109 seems to contain an unusually large number of planetary nebulae for its luminosity.[13] It also contains a substantial amount of dark matter.[14]

Location

NGC 3109 is located about 1.3 megaparsecs (4.2 Mly) away, in the constellation Hydra. This puts it at the very outskirts of the Local Group.[11] Its membership of the Local Group has been challenged, because it seems to be receding faster than estimates of the Local Group's escape velocity.[15] It is distant enough from the largest members of the Local Group that it has not been tidally influenced by them.[12]

Notes

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ 4.0 4.1 Irregular Galaxy NGC 3109
  5. ↑ Grebel, Gallagher, Harbeck, p.7
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ 7.0 7.1 Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ 8.0 8.1 Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ 11.0 11.1 Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ 12.0 12.1 Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.

References

External links

Coordinates: Sky map 10h 03m 06.9s, −26° 09′ 34″

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