NGC 7742[1]
A Hubble Space Telescope (HST) image of NGC 7742.
Credit: NASA/ESA/STScI/AURA.
Observation data (J2000 epoch)
ConstellationPegasus
Right ascension23h 44m 15.7s[2]
Declination+10° 46′ 02″[2]
Redshift0.005547±0.000003[2]
Heliocentric radial velocity1663±1 km/s[2]
Galactocentric velocity1809±6 km/s[2]
Distance72.4 ± 6.2 Mly (22.20 ± 1.90 Mpc)
Apparent magnitude (V)12.35[2]
Characteristics
TypeSA(r)b,[2] LINER/HII[2]
Apparent size (V)1.778 × 1.698 moa[3]
Other designations
UGC 12760,[2] MCG +02-60-010,[2] UZC J234415.8+104601,[2] 2MASX J23441571+1046015[2]

NGC 7742 also known as Fried Egg Galaxy is a face-on unbarred spiral galaxy in the constellation Pegasus. It is also classified as a Type II Seyfert Galaxy.

The galaxy is unusual in that it contains a ring but no bar.[4] Typically, bars are needed to produce a ring structure. The bars' gravitational forces move gas to the ends of the bars, where it forms into the rings seen in many barred spiral galaxies. In this galaxy, however, no bar is present, so this mechanism cannot be used to explain the formation of the ring. O. K. Sil'chenko and A. V. Moiseev proposed that the ring was formed partly as the result of a merger event in which a smaller gas-rich dwarf galaxy collided with NGC 7742. As evidence for this, they point to the unusually bright central region, the presence of highly inclined central gas disk, and the presence of gas that is counterrotating (or rotating in the opposite direction) with respect to the stars.[4]

Two Type II supernovae, SN 1993R and SN 2014cy, have been detected in NGC 7742.[5]

See also

  • NGC 7217 - a face-on spiral galaxy with identical characteristics
  • Sombrero Galaxy - a similar galaxy with a dust ring

References

  1. ↑ Filho, M. E.; Barthel, P. D.; Ho, L. C. (October 2002). "The Nature of Composite LINER/HII Galaxies, Part II". The Astrophysical Journal Supplement. 142 (2): 223–238. arXiv:astro-ph/0205196. Bibcode:2002ApJS..142..223F. doi:10.1086/341786. ISSN 0067-0049. S2CID 16100301.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 "NASA/IPAC Extragalactic Database". Results for NGC 7742. Retrieved 2006-08-20.
  3. ↑ "Centre de Données astronomiques de Strasbourg". Results for NGC 7742. Retrieved 2008-07-09.
  4. 1 2 O. K. Sil'chenko; A. V. Moiseev (2006). "Nature of Nuclear Rings in Unbarred Galaxies: NGC 7742 and NGC 7217". Astronomical Journal. 131 (3): 1336–1346. arXiv:astro-ph/0512431. Bibcode:2006AJ....131.1336S. doi:10.1086/499945. S2CID 14589261.
  5. ↑ "List of Supernovae". IAU Central Bureau for Astronomical Telegrams. Retrieved 13 September 2015.
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