Pegasus Dwarf Irregular Galaxy

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Pegasus Dwarf Irregular Galaxy
Observation data (J2000 epoch)
Right ascension 23h 28m 36.2s[1]
Declination+14° 44′ 35″[1]
Redshift−183 ± 0 km/s[1]
Distance3.0 ± 0.1 Mly (920 ± 30 kpc)[2]
Apparent magnitude (V)13.2[1]
Apparent size (V)5′.0 × 2′.7[1]
Other designations
UGC 12613,[1] PGC 71538,[1] DDO 216,[1] Pegasus Dwarf,[1] PegDIG[1]
See also: Galaxy, List of galaxies

The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is a dwarf irregular galaxy in the direction of the constellation Pegasus. It was discovered by A. G. Wilson in the 1950s. The Pegasus Dwarf is a companion of the Andromeda Galaxy in the Local Group.

General information[edit]

In 1975 Tully & Fisher determined that it was part of the Local Group.[3] The metallicity and the related distance estimate has been subject to discussions in the scientific literature, with varying results; however, recently, by use of the tip of the red giant branch, a distance within 10% error was achieved in 2000[4][5] and then improved to 3% in 2005.[2]

Location of Pegasus Dwarf in the Local Group.

In popular culture[edit]

This galaxy is presumed to be the primary location of the 2004-2009 science fiction television series Stargate Atlantis. While it's mentioned the show takes place in "the Pegasus galaxy" it has not explicitly stated if it is the Irregular or Spheroidal. However, when the Pegasus galaxy has been seen from the Midway station an irregular galaxy is shown. Also, in the discussion regarding the new McKay–Carter Intergalactic Gate Bridge, General Hank Landry states that the distance between the Pegasus and Milky Way galaxies is "three million light-years", suggesting that the series takes place in the Pegasus Dwarf Irregular Galaxy.[6]

See also[edit]


  1. ^ NED gives the galaxy classification as both dIrr and dSph, which means that it is a transitory between dwarf irregular and dwarf spheroidal. It is noted as transitory in Cole et al. 1999.[7]


  1. ^ a b c d e f g h i j k "NASA/IPAC Extragalactic Database". Results for PegDIG. Retrieved 2007-03-15.
  2. ^ a b 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.
  3. ^ Gallager, J S.; Tolstoy, E.; Dohm-Palmer, Robbie C.; Skillman, E D.; Cole, A A.; Hoessel, J G.; Saha, A.; Mateo, M. (1998). "A WIDE FIELD PLANETARY CAMERA 2 STUDY OF THE RESOLVED STELLAR POPULATION OF THE PEGASUS DWARF IRREGULAR GALAXY (DDO 216)". The Astronomical Journal. 115 (5): 1869–1889. doi:10.1086/300328.
  4. ^ Karachentsev, Igor D.; Karachentseva, Valentina E.; Huchtmeier, Walter K.; Makarov, Dmitry I. (2004). "A Catalog of Neighboring Galaxies". The Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
  5. ^ van den Bergh, Sidney (2000). The Galaxies of the Local Group. Cambridge, UK: Cambridge University Press. ISBN 0-521-65181-6.
  6. ^ "The Return" (Stargate Atlantis)
  7. ^ Cole, Andrew A.; Tolstoy, Eline; Gallagher, John S., III; Hoessel, John G.; Mould, Jeremy R.; Holtzman, Jon A.; Saha, Abhijit; Ballester, Gilda E.; Burrows, Christopher J.; Clarke, John T.; Crisp, David; Griffiths, Richard E.; Grillmair, Carl J.; Hester, Jeff J.; Krist, John E.; Meadows, Vikki; Scowen, Paul A.; Stapelfeldt, Karl R.; Trauger, John T.; Watson, Alan M.; Westphal, James R. (1999). "Stellar Populations at the Center of IC 1613". The Astronomical Journal. 118 (4): 1657–1670. arXiv:astro-ph/9905350. Bibcode:1999AJ....118.1657C. doi:10.1086/301042.CS1 maint: Multiple names: authors list (link)

External links[edit]

Coordinates: Sky map 23h 28m 36.2s, +14° 44′ 35″