Omega nebula

(redirected from NGC 6618)

Omega nebula

(Swan nebula; Horseshoe nebula; M17; NGC 6618) An emission nebula with a conspicuous bar that lies at a distance of 2200 parsecs in the constellation of Sagittarius, very close to its northern boundary with Scutum. The nebula's apparent magnitude is 7. It is an H II region and a double radio source. The M17SW molecular cloud is a site of massive star formation; the interface between the nebula and M17SW is an example of an edge-on photodissociation region.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Omega Nebula

[ō′meg·ə ′neb·yə·lə]
(astronomy)
A bright H II region in the constellation Sagittarius that is both a bright far-infrared source and a double radio source. Also known as Swan Nebula.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
M17 is a bright H II region in the Milky Way with a colossal but hidden star cluster cataloged as NGC 6618. It's also the brightest portion of a giant molecular cloud (GMC) located approximately 6,000 light-years away in the Sagittarius spiral arm.
That increase in density, nearly 2 million years ago, kick-started the formation of approximately 12,000 more stars and continues today, making up the huge NGC 6618 star cluster.
The massive O-class stars in NGC 6618 blast out intense ultraviolet radiation that excites the hydrogen gas in the M17 molecular cloud to emit visible light, creating the emission nebula/H II region we're so fond of naming.
These are some of the visible stars of the NGC 6618 cluster.
Although we can't see much of the NGC 6618 cluster, its main concentration of stars is located in the crook between the swan's neck and body.
The object has also been catalogued as Messier 17 (M17) and NGC 6618.
This is M17 (NGC 6618), commonly known as the Swan or Omega nebula, which culminates at a respectable 22[degrees] above the horizon from central England.
M17 (NGC 6618) is a superb diffuse nebula, nicknamed the Omega Nebula.