Omega Nebula

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Omega Nebula
Observation data: J2000 epoch
Type: Emmission
Right ascension: 18h 20m 26s[1]
Declination: −16° 10′ 36″[1]
Distance: 5,000-6,000 ly
Apparent magnitude (V): +6.0[1]
Apparent dimensions (V): 11 arcmins
Constellation: Sagittarius
Physical characteristics
Radius: -
Absolute magnitude (V): -
Notable features: -
Other designations: M17, NGC 6618,
Swan Nebula[1]
See also: Diffuse nebula, Lists of nebulae


The Omega Nebula (also known as the Swan Nebula, M17 or NGC 6618) is an H II region in the constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764. It is located in the rich starfields of the Sagittarius area of the Milky Way.

The distance to the Omega Nebula is between 5,000 and 6,000 light-years and it spans some 15 light-years in diameter. The cloud of interstellar matter of which the nebula is a part is roughly 40 light-years in diameter. The total mass of the Omega Nebula is an estimated 800 solar masses.

A cluster of 35 stars lies embedded in the nebulosity and it is these hot, young stars' radiation that excites the gases in the nebula to shine.

[edit] External links

[edit] References

  1. ^ a b c d SIMBAD Astronomical Database. Results for NGC 6618. Retrieved on 2006-11-16.