Eagle Nebula

This article is about the nebula in the constellation Serpens. For an object in Canis Major, the Seagull Nebula (also called Eagle nebula), see IC 2177. For the astrophotograph, see Pillars of Creation.

Eagle Nebula
A view of the "Spire" within M16, the Eagle Nebula.
Observation data: J2000.0 epoch
Type	Emission
Right ascension	18h 18m 48s[1]
Declination	-13° 49′[1]
Distance	7,000 ly
Apparent magnitude (V)	+6.0[1]
Apparent dimensions (V)	7.0arcmins
Constellation	Serpens
Physical characteristics
Radius	70×55 ly (cluster 15 ly)
Absolute magnitude (V)	-8.21
Notable features	5.5 million years old
Other designations	Messier 16, NGC 6611,[1] Sharpless 49, RCW 165, Gum 83
See also: Diffuse nebula, Lists of nebulae
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The Eagle Nebula (catalogued as Messier 16 or M16, and as NGC 6611) is a young open cluster of stars in the constellation Serpens, discovered by Jean-Philippe de Cheseaux in 1745-46. Its name derives from its shape which is resemblant of an eagle. It is the subject of the famous "Pillars of Creation" photograph by the Hubble Space Telescope, which shows pillars of star-forming gas and dust within the nebula.

Characteristics

The Eagle Nebula is part of a diffuse emission nebula, or H II region, which is catalogued as IC 4703. This region of active current star formation is about 6,500 light-years distant. The tower of gas that can be seen coming off the nebula is approximately 100 trillion km (60 trillion miles) high.

The brightest star in the nebula has an apparent magnitude of +8.24, easily visible with good binoculars.

'Pillars of Creation' region

The "Pillars of Creation" within the Eagle Nebula.

Images made using the Hubble Space Telescope in 1995, by Jeff Hester and Paul Scowen, greatly improved scientific understanding of processes inside the nebula. One of these, a famous photograph known as the "Pillars of Creation", depicts a large region of star formation. Its small, dark areas are believed to be protostars. The pillar structure of the region resembles that of a much larger star formation region, imaged with the Spitzer Space Telescope in 2005, in Cassiopeia, which is designated W5 and has been dubbed the "Pillars of Creation".^[2] These columns––which resemble stalagmites protruding from the floor of a cavern––are composed of interstellar hydrogen gas and dust, which act as incubators for new stars. Inside and on their surface astronomers have found knots or globules of denser gas, called EGGs ("Evaporating Gaseous Globules"). Stars are being formed inside a portion of these EGGs.

Combinations of X-ray images from the Chandra observatory with Hubble's "Pillars" image have shown that X-ray sources (from young stars) do not coincide with the pillars, but instead randomly dot the area.^[1] This suggests that star formation may have peaked approximately one million years ago in the Eagle Nebula and any protostars in the pillar's EGGs are not yet hot enough to emit X-rays.^{[citation needed]}

The longest of the 'Pillars' is seven light years long, and because of their massive density interior gasses contract gravitationally to form stars. At each 'pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. Due to the huge distance between us, the Pillars of Creation may already be gone, and instead a stellar star nursery could have taken its place. In early 2007, scientists using the Spitzer discovered evidence that potentially indicates that the Pillars were destroyed by a nearby supernova explosion about 6,000 years ago, but the light showing the new shape of the nebula will not reach Earth for another millennium.^[3]

In fiction

Main article: Nebulae in fiction#Eagle Nebula

Gallery

• 

  Detail of Hubble image.

• 

  An infrared view of the pillars reveals different structures.

• 

  Three-colour composite mosaic image of the Eagle Nebula.

• 

  Head of Column in the Eagle Nebula.

• 

  Northwestern part of the region, well away from the centre.

References

1. ^ ^{a b c d} "SIMBAD Astronomical Database". Results for NGC 6611. http://simbad.u-strasbg.fr/Simbad. Retrieved 2006-11-16. 
2. ^ Spitzer Captures Cosmic "Mountains Of Creation"
3. ^ Famous Space Pillars Feel the Heat of Star's Explosion - Jet Propulsion Laboratory

External links

• The Eagle's EGGs — ESO Photo Release
• Seds.org, SEDS Messier page on M16
• Spacetelescope.org, Hubble telescope images on M16
• Darkatmospheres.com, Eagle Nebula M16 (wide
• The Eagle Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
• NASA.gov, APOD February 8, 2009 picture Eagle Nebula

See also

Coordinates: 18^h 18^m 48^s, −13° 49′ 00″