Andromeda IV

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Not to be confused with 4 Andromedae.
Andromeda IV
Andromeda IV Hubble WikiSky.jpg
Andromeda IV just about 30″ to the right from TYC 2801-551-1 star (mag: 10.3); HST
Observation data (J2000 epoch)
Constellation Andromeda
Right ascension 00h 42m 32.3s[1]
Declination +40° 34′ 19″[1]
Redshift 256 ± 9 km/s[1]
Type Dwarf irregular[1]
Apparent dimensions (V) 1′.3 × 1′.0[1]
Apparent magnitude (V) 16.6B[1]
Other designations
And IV,[1] PGC 2544[1]
See also: Galaxy, List of galaxies

Coordinates: Sky map 00h 42m 32.3s, +40° 34′ 19″ Andromeda IV (And IV) might be an irregular satellite of the Andromeda Galaxy; however it is more probably not a galaxy at all, but a loosely bound star cluster or some other background feature. In fact, the moderate surface brightness, very blue color, low current star formation rate and low metallicity are consistent with And IV being a small (background) dwarf irregular galaxy, perhaps similar to Local Group dwarfs such as IC 1613 and Sextans A. Arguments based on the observed radial velocity and the tentative detection of the RGB tip suggest it lies well outside the confines of the Local Group. [2]

History[edit]

It was discovered by Sidney van den Bergh.[3]

See also[edit]

References[edit]

  1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database". Results for Andromeda IV. Retrieved 2007-03-15. 
  2. ^ Ferguson, Gallagher, Wyse (2000). "On the nature of Andromeda IV". The Astronomical Journal 120: 821–832. arXiv:astro-ph/0005015. doi:10.1086/301485. 
  3. ^ McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N. (2005). "Distances and metallicities for 17 Local Group galaxies". Monthly Notices of the Royal Astronomical Society 356 (4): 979–997. arXiv:astro-ph/0410489. Bibcode:2005MNRAS.356..979M. doi:10.1111/j.1365-2966.2004.08514.x.