Trifid Nebula

Trifid Nebula
Trifid Nebula by the Hubble Space Telescope (NASA/ESA)
Observation data: J2000 epoch
Type	Emission/Reflection
Right ascension	18h 02m 23s[1]
Declination	-23° 01′ 48″[1]
Distance	5200 ly[2]
Apparent magnitude (V)	+6.3[1]
Apparent dimensions (V)	28 arcmins
Constellation	Sagittarius
Physical characteristics
Other designations	M20, NGC 6514,[1] Sharpless 30, RCW 147, Gum 76
See also: Diffuse nebula, Lists of nebulae
v · d · e

The Trifid Nebula (catalogued as Messier 20 or M20 and as NGC 6514) is an H II region located in Sagittarius. Its name means 'divided into three lobes'. The object is an unusual combination of an open cluster of stars, an emission nebula (the lower, red portion), a reflection nebula (the upper, blue portion) and a dark nebula (the apparent 'gaps' within the emission nebula that cause the trifid appearance; these are also designated Barnard 85). Viewed through a small telescope, the Trifid Nebula is a bright and colorful object, and is thus a perennial favorite of amateur astronomers.^[3]

Characteristics

The Trifid Nebula was the subject of an investigation by astronomers using the Hubble Space Telescope in 1997, using filters that isolate emission from hydrogen atoms, ionized sulfur atoms, and doubly ionized oxygen atom. The images were combined into a false-color composite picture to suggest how the nebula might look to the eye.

The close-up images show a dense cloud of dust and gas, which is a stellar nursery full of embryonic stars. This cloud is about 8 light years away from the nebula's central star. A stellar jet protrudes from the head of the cloud and is about 0.75 light-years long. The jet's source is a young stellar object deep within the cloud. Jets are the exhaust gasses of star formation. Radiation from the nebula's central star makes the jet glow.

The images also showed a finger-like stalk to the right of the jet. It points from the head of the dense cloud directly toward the star that powers the Trifid nebula. This stalk is a prominent example of evaporating gaseous globules, or 'EGGs'. The stalk has survived because its tip is a knot of gas that is dense enough to resist being eaten away by the powerful radiation from the star.

In January, 2005, NASA's Spitzer Space Telescope discovered 30 embryonic stars and 120 newborn stars not seen in visible light images.

It is approximately 5,200 light years away. It is in a magnitude of 6.3.

Gallery

• 

  M20 with amateur telescope

• 

  The Trifid nebula. The outlined area is enlarged right. Credit: NASA/ESA.

• 

  Hubble image of a stellar jet in the Trifid nebula. Credit: NASA/ESA.

• 

  Hubble image, a closer detail of last. Credit: NASA/ESA.

• 

  The Trifid Nebula in infrared as seen by the Spitzer Space Telescope

• 

  The Trifid Nebula is a rare combination of three nebulae types that reveal the fury of freshly formed stars and point to more star birth in the future. Credit: ESO

References

1. ^ ^{a b c d} "SIMBAD Astronomical Database". Results for NGC 6514. http://simbad.u-strasbg.fr/Simbad. Retrieved 2006-11-16. 
2. ^ "Star formation in the Trifid Nebula". Astronomy&Astrophysics 489, 157–171 (2008). http://www.aanda.org/index.php?option=com_article&access=standard&Itemid=129&url=/articles/aa/pdf/2008/37/aa10079-08.pdf. Retrieved 2011-10-09. 
3. ^ "Science Daily". Science Daily article on Trifid Nebula. http://www.sciencedaily.com/releases/2009/08/090826073442.htm. Retrieved 2010-07-06. 

External links

• Spitzer IR Trifid discoveries
• Messier 20, SEDS Messier pages
• Trifid Nebula at ESA/Hubble
• The Trifid Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

See also

• Messier object
• List of Messier objects
• New General Catalogue
• List of nebulas
• Wikipedia Project: Astronomical Objects

Coordinates: 18^h 02^m 23^s, −23° 01′ 48″