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NGC 6946

Coordinates: Sky map 20h 34m 52.3s, +60° 09′ 14″
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NGC 6946
Spiral Galaxy NGC 6946
Observation data (J2000 epoch)
ConstellationCepheus & Cygnus
Right ascension20h 34m 52.3s[1]
Declination+60° 09′ 14″[1]
Redshift0.000160[1]
Heliocentric radial velocity48 ± 2 km/s[1]
Distance22.5 ± 7.8 Mly
(6.9 ± 2.4 Mpc)[2]
Apparent magnitude (V)+9.6[1]
Characteristics
TypeSAB(rs)cd[1]
Apparent size (V)11.5 x 9.8 arcmin[1]
Other designations
UGC 11597, PGC 65001, Arp 29,[1] Caldwell 12

NGC 6946, (also known as the Fireworks Galaxy, Arp 29, and Caldwell 12), is an intermediate spiral galaxy about 18 million light-years away,[2] in the constellations Cepheus and Cygnus. It was discovered by William Herschel on September 9, 1798. NGC 6946 is highly obscured by interstellar matter of the Milky Way galaxy, as it is quite close to the galactic plane. The diameter of the galaxy is approximately 40,000 light-years or just about a third of the size of the Milky Way.[3]

Supernovae

Nine supernovae have been observed in NGC 6946 in the last 100 years: SN 1917A, SN 1939C, SN 1948B, SN 1968D, SN 1969P, SN 1980K, SN 2002hh, SN 2004et, and SN 2008S.[4] This makes it the most prolific known galaxy for this type of event over a period of 100 years. By comparison, the Milky Way galaxy, which has double the number of stars as NGC 6946, averages one supernova event per century.[5]

References

  1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database". Results for NGC 6946. Retrieved 2006-11-18.
  2. ^ a b "Distance Results for NGC 6946". NASA/IPAC Extragalactic Database. Retrieved 2010-06-18.
  3. ^ "Fireworks Galaxy NGC 6946". Astronomy Picture of the Day. 1 January 2011.
  4. ^ "List of Supernovae". Harvard-Smithsonian Center for Astrophysics (IAU). Retrieved 2010-07-12.
  5. ^ "Gemini Observatory Welcomes 2005 with Release of Galactic Fireworks Image", Gemini Observatory, January 1, 2005, retrieved 2016-01-04.

External links



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