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Created page with "{{Night Sky | image = | designation =V4647 Sagittarii | rightascension =17<sup>h</sup> 46<sup>m</sup> 15.240<sup>s</sup><ref name=simbad>[https://simbad.u-stras..."
{{Night Sky
| image =
| designation =V4647 Sagittarii
| rightascension =17<sup>h</sup> 46<sup>m</sup> 15.240<sup>s</sup><ref name=simbad>[https://simbad.u-strasbg.fr/simbad/sim-id?Ident=V4647+Sagittarii&submit=submit+id Pistol star] from the [http://simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>
| declination =-28° 50′ 03.58″<ref name=simbad/>
| distance =25,000 ly<ref name=constellation-guide>{{cite web|url=https://www.constellation-guide.com/pistol-star/|title=Pistol star|accessdate=2019-03-06}}</ref>
| constellation =Sagittarius
| type =Hypergiant
| dimensions =
| magnitude =Apparent Mag: >28<ref name=constellation-guide/><br/>Absolute Mag: -10.75<ref name=constellation-guide/>
| redshift =
| radvelocity =
| propmotion =
| parallax =
}}
The '''Pistol star''' (V4647 Sagittarii) is a blue [[hypergiant star]] found in the constellation of [[Sagittarius]].<ref name=constellation-guide/> The star is situated in the [[Pistol nebula]] and cannot be viewed directly in [[visible light]] due to the obscuring effects of dust. However this can be negated by observing in the [[infrared]] and such observations have revealed the star to be one of the most luminous ever discovered, at approximately 1,600,000 times more luminous than the [[Sun]].<ref name=constellation-guide/> It is suspected of being a luminous blue [[variable star|variable]].
The star was discovered in 1990 by Don Figer using the [[Hubble Space Telescope]].<ref name=constellation-guide/> Later in 1995 it was suggested the material composing the surrounding nebula might originate from the Pistol star.<ref name=nasa>{{cite web|url=https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question21.html|title=What is the biggest star we know?|accessdate=2019-03-06}}</ref> This was confirmed by the Hubble Space Telescope in 1997.<ref name=nasa/><ref>{{cite web|url=http://hubblesite.org/image/524/news_release/1997-33|title=The Pistol Star: A Brilliant Star in Milky Way's Core|accessdate=2019-03-06}}</ref>
==Properties and structure==
Lying 25,000 [[light year]]s from [[Earth]], the Pistol star is one of the brightest known stars.<ref name=constellation-guide/> The star is truly a giant, its [[mass (physics)|mass]] has been estimated from its spectrum to be 27.5 times that of the [[Sun]]. Its radius is 306 times greater (larger than the distance between the earth and the sun) and the star generates a [[stellar wind]] that is more than 10 billion times more powerful than that of the Sun. The star is therefore shedding vast quantities of material from its surface. It is thought the star radiates as much [[energy]] in 20 seconds as the Sun does in an entire year.<ref name=constellation-guide/> However it is a long way from being the largest known star; others such as [[UY Scuti]] and [[VY Canis Majoris]] are far larger.<ref name=universeguide>{{cite web|url=https://www.universeguide.com/star/pistolstar|title=Pistol star|accessdate=2019-03-06}}</ref>
The surface of the star is extremely hot at 11,800 [[kelvin]] making it appear blue.<ref name=constellation-guide/> Due to the absorbing effects of dust, the star has an apparent magnitude of at least +28, but if there were no dust, it would be +4 and so visible to the unaided eye.<ref name=constellation-guide/> The enveloping nebula contains (excluding the Pistol star) around 9.3 [[solar mass]]es of material. There can be seen to be two concentric shells of material, the larger of the two is thought to be 4 [[light year]]s across and is currently expanding at 60 km/s.<ref name=arxiv>Figer, D., Morris, M., Geballe, T., Rich, R., Serabyn, E., McLean, I., Puetter, R. and Yahil, A. (1999). High-Resolution Infrared Imaging and Spectroscopy of the Pistol Nebula: Evidence for Ejection. ''The Astrophysical Journal'', 525(2), pp.759-771. [https://arxiv.org/abs/astro-ph/9906479 arXiv:astro-ph/9906479]</ref>
==References==
{{reflist}}
{{Stars}}
[[Category:Astronomy]]
[[Category:Stars]]
| image =
| designation =V4647 Sagittarii
| rightascension =17<sup>h</sup> 46<sup>m</sup> 15.240<sup>s</sup><ref name=simbad>[https://simbad.u-strasbg.fr/simbad/sim-id?Ident=V4647+Sagittarii&submit=submit+id Pistol star] from the [http://simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>
| declination =-28° 50′ 03.58″<ref name=simbad/>
| distance =25,000 ly<ref name=constellation-guide>{{cite web|url=https://www.constellation-guide.com/pistol-star/|title=Pistol star|accessdate=2019-03-06}}</ref>
| constellation =Sagittarius
| type =Hypergiant
| dimensions =
| magnitude =Apparent Mag: >28<ref name=constellation-guide/><br/>Absolute Mag: -10.75<ref name=constellation-guide/>
| redshift =
| radvelocity =
| propmotion =
| parallax =
}}
The '''Pistol star''' (V4647 Sagittarii) is a blue [[hypergiant star]] found in the constellation of [[Sagittarius]].<ref name=constellation-guide/> The star is situated in the [[Pistol nebula]] and cannot be viewed directly in [[visible light]] due to the obscuring effects of dust. However this can be negated by observing in the [[infrared]] and such observations have revealed the star to be one of the most luminous ever discovered, at approximately 1,600,000 times more luminous than the [[Sun]].<ref name=constellation-guide/> It is suspected of being a luminous blue [[variable star|variable]].
The star was discovered in 1990 by Don Figer using the [[Hubble Space Telescope]].<ref name=constellation-guide/> Later in 1995 it was suggested the material composing the surrounding nebula might originate from the Pistol star.<ref name=nasa>{{cite web|url=https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question21.html|title=What is the biggest star we know?|accessdate=2019-03-06}}</ref> This was confirmed by the Hubble Space Telescope in 1997.<ref name=nasa/><ref>{{cite web|url=http://hubblesite.org/image/524/news_release/1997-33|title=The Pistol Star: A Brilliant Star in Milky Way's Core|accessdate=2019-03-06}}</ref>
==Properties and structure==
Lying 25,000 [[light year]]s from [[Earth]], the Pistol star is one of the brightest known stars.<ref name=constellation-guide/> The star is truly a giant, its [[mass (physics)|mass]] has been estimated from its spectrum to be 27.5 times that of the [[Sun]]. Its radius is 306 times greater (larger than the distance between the earth and the sun) and the star generates a [[stellar wind]] that is more than 10 billion times more powerful than that of the Sun. The star is therefore shedding vast quantities of material from its surface. It is thought the star radiates as much [[energy]] in 20 seconds as the Sun does in an entire year.<ref name=constellation-guide/> However it is a long way from being the largest known star; others such as [[UY Scuti]] and [[VY Canis Majoris]] are far larger.<ref name=universeguide>{{cite web|url=https://www.universeguide.com/star/pistolstar|title=Pistol star|accessdate=2019-03-06}}</ref>
The surface of the star is extremely hot at 11,800 [[kelvin]] making it appear blue.<ref name=constellation-guide/> Due to the absorbing effects of dust, the star has an apparent magnitude of at least +28, but if there were no dust, it would be +4 and so visible to the unaided eye.<ref name=constellation-guide/> The enveloping nebula contains (excluding the Pistol star) around 9.3 [[solar mass]]es of material. There can be seen to be two concentric shells of material, the larger of the two is thought to be 4 [[light year]]s across and is currently expanding at 60 km/s.<ref name=arxiv>Figer, D., Morris, M., Geballe, T., Rich, R., Serabyn, E., McLean, I., Puetter, R. and Yahil, A. (1999). High-Resolution Infrared Imaging and Spectroscopy of the Pistol Nebula: Evidence for Ejection. ''The Astrophysical Journal'', 525(2), pp.759-771. [https://arxiv.org/abs/astro-ph/9906479 arXiv:astro-ph/9906479]</ref>
==References==
{{reflist}}
{{Stars}}
[[Category:Astronomy]]
[[Category:Stars]]