NGC 45

NGC 45
NGC 45 by DECam
Observation data (2000.0 epoch)
ConstellationCetus
Right ascension00° 14′ 03.989″[1]
Declination–23h 10m 55.53s[1]
Redshift0.001558[2]
Heliocentric radial velocity466 km/s[3]
Distance21.7 Mly (6.64 Mpc)[4]
Apparent magnitude (V)10.73±0.03[5]
Apparent magnitude (B)11.21±0.03[5]
Characteristics
TypeSA(s)dm[6]
Mass/Light ratio[7] M☉/L☉
Apparent size (V)7.41′ × 5.13'
Other designations
UGCA 4, LEDA 930, MCG -04-01-21, PGC 930[8]

NGC 45 is a low surface brightness[7] spiral galaxy in the equatorial constellation of Cetus. It was discovered on 11 November 1835 by the English astronomer John Herschel.[9] The galaxy is located at a distance of 22[4] million light years and is receding with a heliocentric radial velocity of 466 km/s.[3] It is located in the vicinity of the Sculptor Group, but is most likely a background galaxy.[7]

The morphological class of NGC 45 is SA(s)dm,[6] indicating this is a spiral galaxy with no prominent inner bar (SA) or ring (s) feature. There is no central bulge to speak of.[7] The galactic plane is inclined at an angle of 55°±5° to the line of sight from the Earth, with the major axis of the elliptical profile being aligned along a position angle of 145°±5°.[7] Star formation is proceeding at a modest rate of ~0.20 M☉·yr−1.[6]

Unlike the Milky Way, NGC 45 has no clearly defined spiral arms, and its center bar nucleus is also very small and distorted. NGC 45 thus does not have a galactic habitable zone.[10][11][12] For the Milky Way, the galactic habitable zone is commonly believed to be an annulus with an outer radius of about 10 kiloparsecs and an inner radius close to the Galactic Center, both of which lack hard boundaries.[11]

  1. ^ a b Cite error: The named reference Skrutskie_et_al_2006 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference ned was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Tully_et_al_2016 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Karachentsev_et_al_2016 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Cook_et_al_2014 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Pannuti_et_al_2015 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference Chemin_et_al_2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Seligman was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Gowanlock_et_al_2011 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference gowanlock-2011 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SP-20150821 was invoked but never defined (see the help page).