SkipCaptcha
1,279
edits
Changes
Jump to navigation
Jump to search
Created page with "{{Night Sky | image = | designation =Messier 57 NGC 6720 | rightascension =18<sup>h</sup> 53<sup>m</sup> 35.079<sup>s</sup> | declination..."
{{Night Sky
| image =
| designation =[[Messier catalogue|Messier 57]]
NGC 6720
| rightascension =18<sup>h</sup> 53<sup>m</sup> 35.079<sup>s</sup>
| declination =-33° 01′ 45.03″
| distance =2,300 ly
| constellation =[[Lyra]]
| type =[[Planetary nebula]]
| dimensions = 1'
| magnitude =8.8
| redshift =
| radvelocity =-21 km/s
| propmotion =
| parallax =
}}
The '''Ring nebula''' (M57, NGC 6720) is a [[planetary nebula]] in the [[constellation]] of [[Lyra]].<ref name=seds>[http://www.messier.seds.org/m/m057.html M57] from messier.ses.org</ref> It is one of the four planetary nebulae in the [[Messier catalogue]].<ref name=messier-objects>[http://www.messier-objects.com/messier-57-ring-nebula/ Messier 57] from messier-objects.com</ref> The nebula is well known for its spectacular colours. The nebula is approaching [[Earth]] at 21 km/s
==History==
Messier 57 was first observed by [[Charles Messier]] in 1779 and was the second such object discovered.<ref name=seds/> Messier was also the first to observe a [[planetary nebula]], the first being the [[Dumbbell nebula]]. The astronomer Antoine Darquier de Pellepoix found the object a few days later, leading to long-standing error that Darquier discovered M57 as Messier described Darquier's observation as a discovery.<ref name=seds/> Darquier described the nebula as having, "the apparent dimension of Jupiter," and that it, "is perfectly round and sharply limited." This comparison to a [[planet]] may be what caused [[William Herschel]] to describe the object and others like it as "planetary nebulae." William Herschel was the first to observe the nebula's ring like structure in the 1780s and believed its appearance may be due to unresolved [[star]]s.<ref name=messier-objects/> This was disproven in 1864 when spectroscopic analysis of the nebula by William Huggins produced spectra like that of fluorescent gases.<ref name=constellation-guide>[http://www.constellation-guide.com/ring-nebula-m57-in-lyra/ Ring nebula M57 in Lyra] from constellation-guide.com</ref> The first [[photograph]]s of the nebula were taken in 1896 by Jenő Gothard.
==Properties and Structure==
The nebula consists of gases expanding in an [[ellipse|oval]] shape, with a faint star at its centre. The star is likely to be a [[white dwarf]] and has a magnitude of 14.8, making difficult to observe.<ref name=messier-objects/> The ring has a diameter of 2.4 [[light year]]s and is expanding at approximately 20-30 km/year. The ultraviolet radiation emitted by the star illuminates the nebula. The nebula is thought to be shaped like a [[torus]], similar to the [[Dumbbell nebula]]. However, from Earth the nebula is viewed from one of its poles, leading to a ring like appearance.
===Composition===
The ring of the nebula is composed of a variety of different [[element]]s. The [[mass (science)|mass]] of the gas is estimated to be 0.2 solar masses and have an average [[density]] of 10,000 [[ion]]s per cubic centimeter.<ref name=seds/> The composition by each element relative to the number of [[fluorine]] ions is as follows:<ref name=seds/>
{| class="wikitable"
|+
! scope="col" | Element
! scope="col" | Number of Ions
|-
| [[Hydrogen]] || 4,250,000
|-
| [[Helium]] || 337,500
|-
| [[Oxygen]] || 2,500
|-
| [[Nitrogen]] || 1,250
|-
| [[Neon]] || 375
|-
| [[Sulfur]] || 225
|-
| [[Argon]] || 30
|-
| [[Chlorine]] || 9
|-
| [[Fluorine]] || 1
|}
Each colour corresponds to the decay of an excited state to a lower energy state, with the colour depending on the difference of energy between the states. For example, the blue comes from helium, the yellow/green from oxygen and the red by nitrogen.
===Central Star===
The central star is believed to be a [[white dwarf]], with a mass of 0.6 solar masses and a luminosity 200 times that of the [[Sun]].<ref name=messier-objects/> It's temperature is thought to be 125,000 kelvin, though some estimates place it higher, at 150,000 kelvin.<ref name=messier-objects/><ref name=illinois>[http://stars.astro.illinois.edu/sow/ring-p.html Ring nebula] from stars.astro.illinois.edu</ref> The star appears faint (14.8 mag) as its great [[temperature]] means much of its emissions are in the [[ultraviolet]] portion of the [[electromagnetic spectrum]].
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
[[Category:Messier Objects]]
| image =
| designation =[[Messier catalogue|Messier 57]]
NGC 6720
| rightascension =18<sup>h</sup> 53<sup>m</sup> 35.079<sup>s</sup>
| declination =-33° 01′ 45.03″
| distance =2,300 ly
| constellation =[[Lyra]]
| type =[[Planetary nebula]]
| dimensions = 1'
| magnitude =8.8
| redshift =
| radvelocity =-21 km/s
| propmotion =
| parallax =
}}
The '''Ring nebula''' (M57, NGC 6720) is a [[planetary nebula]] in the [[constellation]] of [[Lyra]].<ref name=seds>[http://www.messier.seds.org/m/m057.html M57] from messier.ses.org</ref> It is one of the four planetary nebulae in the [[Messier catalogue]].<ref name=messier-objects>[http://www.messier-objects.com/messier-57-ring-nebula/ Messier 57] from messier-objects.com</ref> The nebula is well known for its spectacular colours. The nebula is approaching [[Earth]] at 21 km/s
==History==
Messier 57 was first observed by [[Charles Messier]] in 1779 and was the second such object discovered.<ref name=seds/> Messier was also the first to observe a [[planetary nebula]], the first being the [[Dumbbell nebula]]. The astronomer Antoine Darquier de Pellepoix found the object a few days later, leading to long-standing error that Darquier discovered M57 as Messier described Darquier's observation as a discovery.<ref name=seds/> Darquier described the nebula as having, "the apparent dimension of Jupiter," and that it, "is perfectly round and sharply limited." This comparison to a [[planet]] may be what caused [[William Herschel]] to describe the object and others like it as "planetary nebulae." William Herschel was the first to observe the nebula's ring like structure in the 1780s and believed its appearance may be due to unresolved [[star]]s.<ref name=messier-objects/> This was disproven in 1864 when spectroscopic analysis of the nebula by William Huggins produced spectra like that of fluorescent gases.<ref name=constellation-guide>[http://www.constellation-guide.com/ring-nebula-m57-in-lyra/ Ring nebula M57 in Lyra] from constellation-guide.com</ref> The first [[photograph]]s of the nebula were taken in 1896 by Jenő Gothard.
==Properties and Structure==
The nebula consists of gases expanding in an [[ellipse|oval]] shape, with a faint star at its centre. The star is likely to be a [[white dwarf]] and has a magnitude of 14.8, making difficult to observe.<ref name=messier-objects/> The ring has a diameter of 2.4 [[light year]]s and is expanding at approximately 20-30 km/year. The ultraviolet radiation emitted by the star illuminates the nebula. The nebula is thought to be shaped like a [[torus]], similar to the [[Dumbbell nebula]]. However, from Earth the nebula is viewed from one of its poles, leading to a ring like appearance.
===Composition===
The ring of the nebula is composed of a variety of different [[element]]s. The [[mass (science)|mass]] of the gas is estimated to be 0.2 solar masses and have an average [[density]] of 10,000 [[ion]]s per cubic centimeter.<ref name=seds/> The composition by each element relative to the number of [[fluorine]] ions is as follows:<ref name=seds/>
{| class="wikitable"
|+
! scope="col" | Element
! scope="col" | Number of Ions
|-
| [[Hydrogen]] || 4,250,000
|-
| [[Helium]] || 337,500
|-
| [[Oxygen]] || 2,500
|-
| [[Nitrogen]] || 1,250
|-
| [[Neon]] || 375
|-
| [[Sulfur]] || 225
|-
| [[Argon]] || 30
|-
| [[Chlorine]] || 9
|-
| [[Fluorine]] || 1
|}
Each colour corresponds to the decay of an excited state to a lower energy state, with the colour depending on the difference of energy between the states. For example, the blue comes from helium, the yellow/green from oxygen and the red by nitrogen.
===Central Star===
The central star is believed to be a [[white dwarf]], with a mass of 0.6 solar masses and a luminosity 200 times that of the [[Sun]].<ref name=messier-objects/> It's temperature is thought to be 125,000 kelvin, though some estimates place it higher, at 150,000 kelvin.<ref name=messier-objects/><ref name=illinois>[http://stars.astro.illinois.edu/sow/ring-p.html Ring nebula] from stars.astro.illinois.edu</ref> The star appears faint (14.8 mag) as its great [[temperature]] means much of its emissions are in the [[ultraviolet]] portion of the [[electromagnetic spectrum]].
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
[[Category:Messier Objects]]