Trifid Nebula
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| Trifid Nebula | |
 Trifid Nebula by the Hubble Space Telescope (NASA/ESA) |
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| Observation data: J2000 epoch | |
|---|---|
| Type | Emission/Reflection |
| Right ascension | 18h 02m 23s[1] |
| Declination | -23° 01′ 48″[1] |
| Distance | 2000 - 9000 ly |
| Apparent magnitude (V) | +6.3[1] |
| Apparent dimensions (V) | ~20 arcmins |
| Constellation | Sagittarius |
| Physical characteristics | |
| Radius | - |
| Absolute magnitude (V) | - |
| Notable features | - |
| Other designations | M20, NGC 6514[1], Sharpless 30, RCW 147, Gum 76 |
| See also: Diffuse nebula, Lists of nebulae | |
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.
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[edit] 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 atoms. 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 an 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.
[edit] Gallery
 M20 Amateur Image Courtesy Hunter Wilson |
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 The Trifid Nebula in infrared as seen by the Spitzer Space Telescope |
 Credit:Adam Block-Mount Lemmon SkyCenter. University of Arizona (Board of Regents) |
[edit] See also
[edit] 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
[edit] References
- ^ a b c d "SIMBAD Astronomical Database". Results for NGC 6514. http://simbad.u-strasbg.fr/Simbad. Retrieved on 2006-11-16.
Coordinates: 
18h 02m 23s, −23° 01′ 48″
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