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Created page with "{{Night Sky | image = | designation =Messier 20 NGC 6514 | rightascension =18<sup>h</sup> 02<sup>m</sup> 23<sup>s</sup> | declination..."
{{Night Sky
| image =
| designation =[[Messier catalogue|Messier 20]]
NGC 6514
| rightascension =18<sup>h</sup> 02<sup>m</sup> 23<sup>s</sup>
| declination =-23° 01′ 48″
| distance =5,200 ly
| constellation =[[Sagittarius]]
| type =[[nebula]]
| dimensions = 28.0'
| magnitude = 6.3
| redshift =
| radvelocity =
| propmotion =
| parallax =
}}
The '''Trifid nebula''' (M20, NGC 6514) is a [[nebula]] in the [[constellation]] of [[Sagittarius]].<ref name=messier-objects>[http://www.messier-objects.com/messier-20-trifid-nebula/ Trifid nebula] from messier-objects.com</ref> Found only 2 degrees from the larger [[Lagoon nebula]], the Trifid nebula is a well known star forming region and houses several different types of nebulae, including: an [[emission nebula]], a [[reflection nebula]], a [[dark nebula]] and an [[open cluster]]. Its name derives from its three lobes. It is relatively ease to observe through small telescopes and its proximity to the Lagoon nebula makes it a popular target for astronomers. It is best seen from the southern and equatorial regions in late summer.<ref>[https://freestarcharts.com/messier-20 Messier 20] from freestarcharts.com</ref> The nebula has often been mentioned in works of [[science-fiction]].
==History==
The nebula was first observed by [[Charles Messier]] on 5<sup>th</sup> June 1764 and added it as the 20th item in his [[Messier catalogue|catalogue]].<ref name=seds>[http://www.messier.seds.org/m/m020.html M20] from messier.seds.org</ref> Specifically, Messier observed the star cluster, describing it as a cluster of stars of the 8th or 8th magnitude. While Messier identified the star cluster and on later inspection some nebulosity surrounding it, it was [[William Herschel]] in 1784 who noted there were three different nebulae that combined to form the Trifid nebula. His son, [[John Herschel]], was the first to refer to the nebula as the "Trifid nebula" in 1826.<ref name=messier-objects/> Much later in 1919, Edward Barnard catalogued the [[dark nebula]] responsible for the Trifid nebula's distinctive shape as Barnard 85.<ref name=messier-objects/>
==Properties and Structure==
The nebula consists of several different types of nebulae. At its centre is a blue [[open star cluster]] which is surrounded by a red [[emission nebula]].<ref name=seds/> These hot stars produce large quantities of [[ultraviolet]] radiation, ionizing the surrounding hydrogen gas.<ref>[https://www.noao.edu/image_gallery/html/im0587.html Trifid, M20, NGC 6514] from the [https://www.noao.edu/ National Optical Astronomy Observatory]</ref> When the ionzed hydrogen recombine, the distinctive hydrogen alpha red is emitted. This emission nebula is enclosed by a blue [[reflection nebula]], most noticeable in the northern most parts of the nebula. Here, the radiation from the central star cluster is too weak to cause ionization, so instead the blue light of the hot stars is simply reflected off gas and dust. This gives rise to a blue appearance. A [[dark nebula]] in the foreground is responsible for the characteristic three lobes. There may also be a [[supernova]] remnant in the nebula.<ref>[https://arxiv.org/abs/astro-ph/0003295 Radio continuum emission from the central stars of M20 and the detection of a new supernova remnant near M20]</ref>
There is large uncertainty in the distance to the Trifid nebula, with some sources putting it as low as 2,200 [[light year]]s and others at around 9,000 light years.<ref name=seds/> It has a linear diameter of approximately 42 ly and is fairly bright with an apparent [[Star magnitude|magnitude]] of 6.3 (though some sources suggest it is somewhat fainter at around 9).<ref name=constellation-guide>[http://www.constellation-guide.com/trifid-nebula-messier-20/ Trifid nebula] from constellation-guide.com</ref> The Nebula also contains some stellar jets and an evaporating gaseous globule, or EGG.<ref>[https://www.universetoday.com/31733/messier-20/ Messier 20] from universetoday.com</ref>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
[[Category:Messier Objects]]
| image =
| designation =[[Messier catalogue|Messier 20]]
NGC 6514
| rightascension =18<sup>h</sup> 02<sup>m</sup> 23<sup>s</sup>
| declination =-23° 01′ 48″
| distance =5,200 ly
| constellation =[[Sagittarius]]
| type =[[nebula]]
| dimensions = 28.0'
| magnitude = 6.3
| redshift =
| radvelocity =
| propmotion =
| parallax =
}}
The '''Trifid nebula''' (M20, NGC 6514) is a [[nebula]] in the [[constellation]] of [[Sagittarius]].<ref name=messier-objects>[http://www.messier-objects.com/messier-20-trifid-nebula/ Trifid nebula] from messier-objects.com</ref> Found only 2 degrees from the larger [[Lagoon nebula]], the Trifid nebula is a well known star forming region and houses several different types of nebulae, including: an [[emission nebula]], a [[reflection nebula]], a [[dark nebula]] and an [[open cluster]]. Its name derives from its three lobes. It is relatively ease to observe through small telescopes and its proximity to the Lagoon nebula makes it a popular target for astronomers. It is best seen from the southern and equatorial regions in late summer.<ref>[https://freestarcharts.com/messier-20 Messier 20] from freestarcharts.com</ref> The nebula has often been mentioned in works of [[science-fiction]].
==History==
The nebula was first observed by [[Charles Messier]] on 5<sup>th</sup> June 1764 and added it as the 20th item in his [[Messier catalogue|catalogue]].<ref name=seds>[http://www.messier.seds.org/m/m020.html M20] from messier.seds.org</ref> Specifically, Messier observed the star cluster, describing it as a cluster of stars of the 8th or 8th magnitude. While Messier identified the star cluster and on later inspection some nebulosity surrounding it, it was [[William Herschel]] in 1784 who noted there were three different nebulae that combined to form the Trifid nebula. His son, [[John Herschel]], was the first to refer to the nebula as the "Trifid nebula" in 1826.<ref name=messier-objects/> Much later in 1919, Edward Barnard catalogued the [[dark nebula]] responsible for the Trifid nebula's distinctive shape as Barnard 85.<ref name=messier-objects/>
==Properties and Structure==
The nebula consists of several different types of nebulae. At its centre is a blue [[open star cluster]] which is surrounded by a red [[emission nebula]].<ref name=seds/> These hot stars produce large quantities of [[ultraviolet]] radiation, ionizing the surrounding hydrogen gas.<ref>[https://www.noao.edu/image_gallery/html/im0587.html Trifid, M20, NGC 6514] from the [https://www.noao.edu/ National Optical Astronomy Observatory]</ref> When the ionzed hydrogen recombine, the distinctive hydrogen alpha red is emitted. This emission nebula is enclosed by a blue [[reflection nebula]], most noticeable in the northern most parts of the nebula. Here, the radiation from the central star cluster is too weak to cause ionization, so instead the blue light of the hot stars is simply reflected off gas and dust. This gives rise to a blue appearance. A [[dark nebula]] in the foreground is responsible for the characteristic three lobes. There may also be a [[supernova]] remnant in the nebula.<ref>[https://arxiv.org/abs/astro-ph/0003295 Radio continuum emission from the central stars of M20 and the detection of a new supernova remnant near M20]</ref>
There is large uncertainty in the distance to the Trifid nebula, with some sources putting it as low as 2,200 [[light year]]s and others at around 9,000 light years.<ref name=seds/> It has a linear diameter of approximately 42 ly and is fairly bright with an apparent [[Star magnitude|magnitude]] of 6.3 (though some sources suggest it is somewhat fainter at around 9).<ref name=constellation-guide>[http://www.constellation-guide.com/trifid-nebula-messier-20/ Trifid nebula] from constellation-guide.com</ref> The Nebula also contains some stellar jets and an evaporating gaseous globule, or EGG.<ref>[https://www.universetoday.com/31733/messier-20/ Messier 20] from universetoday.com</ref>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
[[Category:Messier Objects]]