SkipCaptcha
1,279
edits
Changes
Jump to navigation
Jump to search
Created page with "{{Night Sky | image = | designation =IC 4406 | rightascension =14<sup>h</sup> 22<sup>m</sup> 26.21<sup>s</sup><ref name=simbad>[http://simbad.u-strasbg.fr/simba..."
{{Night Sky
| image =
| designation =IC 4406
| rightascension =14<sup>h</sup> 22<sup>m</sup> 26.21<sup>s</sup><ref name=simbad>[http://simbad.u-strasbg.fr/simbad/sim-id?Ident=IC4406&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id IC 4406] from the [simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>
| declination =-44° 09′ 02.0″<ref name=simbad/>
| distance =3,500 ly<ref name=spitzer>[http://www.spitzer.caltech.edu/images/5189-sig12-006a-The-Boxy-Retina-Nebula The Boxy Retina Nebula] from spitzer.caltech.edu</ref>
| constellation =Lupus
| type =Planetary nebula
| dimensions =100" x 30"<ref name=arxiv>Smith, C., Zijlstra, A. and Fuller, G. (2015). A molecular line survey of a sample of AGB stars and planetary nebulae. ''Monthly Notices of the Royal Astronomical Society'', 454(1), pp.177-200. [https://arxiv.org/abs/1508.05014 arXiv:1508.05014]</ref>
| magnitude =
| redshift =
| radvelocity =-22±5 km/s<ref name=simbad/>
| propmotion =
| parallax =
}}
The '''Retina nebula''' (IC 4406) is a [[planetary nebula]] in the southern [[constellation]] of [[Lupus]].<ref name=spitzer/> The nebula possess an unusually rectangular structure with a [[white dwarf|white dwarf star]] at its centre. The nebula is uncommon as it has [[dust]] lanes that can be seen to weave their way across the nebula. These dust lanes are incredibly intricate and the nebula's name arises from a comparison of these dust lanes to the [[retina]] of the [[eye]].<ref name=annesastronomy>[http://annesastronomynews.com/photo-gallery-ii/nebulae-clouds/the-retina-nebula-ic-4406/ The Retina Nebula, a bipolar planetary nebula in Lupus] from annesastronomynews.com</ref>
==Properties and Structure==
The Retina nebula is a bipolar planetary nebula meaning it consists of two enormous lobes diametrically opposed to each other, forming a shape very similar to a hollow [[cylinder]].<ref name=apod>[https://apod.nasa.gov/apod/ap170108.html IC 4406: A Seemingly Square Nebula] from apod.nasa.gov</ref> We see the curved face of the cylinder resulting in the nebula's rectangular appearance. It is thought if we were able to view the nebula from the top, it would appear circular like other planetary nebulae such as the [[Ring nebula]] or the [[Owl nebula]]. The precise distance the nebula is rather uncertain with estimates ranging from 2,000-5,000 [[light year]]s.<ref name=spitzer/> This means it's apparent size of 100 arcminutes long corresponds to a physical size of 0.97-2.4 light years.<ref>By direct calculation using the given apparent length of 100" and distances of 2,000 and 5,000 light years.</ref>
There are a large number of dark [[dust]] lanes that cross the nebula and these are thought to be approximately 160 [[AU]] across.<ref name=annesastronomy/> Various [[:element]]s, including [[helium]], [[oxygen]], [[nitrogen]], [[neon]] and [[argon]], have been found in the nebula with a roughly uniform concentration along the nebula.<ref>Corradi, R., Perinotto, M., Schwarz, H. and Claeskens, J. (1997). The chemical structure of bipolar planetary nebulae. I. IC 4406. ''Astronomy and Astrophysics'', 322, pp.975-981. [http://adsabs.harvard.edu/abs/1997A%26A...322..975C Online]</ref> The nebula is believed to also possess a relatively [[density|dense]] [[torus]] at its [[equator]] like many other planetary nebulae.<ref>Sahai, R., Wootten, A., Schwarz, H. and Clegg, R. (1991). The bipolar planetary nebula IC 4406 - CO, optical and dust emission. ''Astronomy and Astrophysics'', 251(2), pp.560-574. [http://adsabs.harvard.edu/abs/1991A&A...251..560S Online]</ref> At the centre of the nebula is a [[white dwarf]] that is thought to have a temperature of some 80,000 kelvin.<ref name=arxiv/>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
| image =
| designation =IC 4406
| rightascension =14<sup>h</sup> 22<sup>m</sup> 26.21<sup>s</sup><ref name=simbad>[http://simbad.u-strasbg.fr/simbad/sim-id?Ident=IC4406&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id IC 4406] from the [simbad.u-strasbg.fr/simbad SIMBAD Astronomical Database]</ref>
| declination =-44° 09′ 02.0″<ref name=simbad/>
| distance =3,500 ly<ref name=spitzer>[http://www.spitzer.caltech.edu/images/5189-sig12-006a-The-Boxy-Retina-Nebula The Boxy Retina Nebula] from spitzer.caltech.edu</ref>
| constellation =Lupus
| type =Planetary nebula
| dimensions =100" x 30"<ref name=arxiv>Smith, C., Zijlstra, A. and Fuller, G. (2015). A molecular line survey of a sample of AGB stars and planetary nebulae. ''Monthly Notices of the Royal Astronomical Society'', 454(1), pp.177-200. [https://arxiv.org/abs/1508.05014 arXiv:1508.05014]</ref>
| magnitude =
| redshift =
| radvelocity =-22±5 km/s<ref name=simbad/>
| propmotion =
| parallax =
}}
The '''Retina nebula''' (IC 4406) is a [[planetary nebula]] in the southern [[constellation]] of [[Lupus]].<ref name=spitzer/> The nebula possess an unusually rectangular structure with a [[white dwarf|white dwarf star]] at its centre. The nebula is uncommon as it has [[dust]] lanes that can be seen to weave their way across the nebula. These dust lanes are incredibly intricate and the nebula's name arises from a comparison of these dust lanes to the [[retina]] of the [[eye]].<ref name=annesastronomy>[http://annesastronomynews.com/photo-gallery-ii/nebulae-clouds/the-retina-nebula-ic-4406/ The Retina Nebula, a bipolar planetary nebula in Lupus] from annesastronomynews.com</ref>
==Properties and Structure==
The Retina nebula is a bipolar planetary nebula meaning it consists of two enormous lobes diametrically opposed to each other, forming a shape very similar to a hollow [[cylinder]].<ref name=apod>[https://apod.nasa.gov/apod/ap170108.html IC 4406: A Seemingly Square Nebula] from apod.nasa.gov</ref> We see the curved face of the cylinder resulting in the nebula's rectangular appearance. It is thought if we were able to view the nebula from the top, it would appear circular like other planetary nebulae such as the [[Ring nebula]] or the [[Owl nebula]]. The precise distance the nebula is rather uncertain with estimates ranging from 2,000-5,000 [[light year]]s.<ref name=spitzer/> This means it's apparent size of 100 arcminutes long corresponds to a physical size of 0.97-2.4 light years.<ref>By direct calculation using the given apparent length of 100" and distances of 2,000 and 5,000 light years.</ref>
There are a large number of dark [[dust]] lanes that cross the nebula and these are thought to be approximately 160 [[AU]] across.<ref name=annesastronomy/> Various [[:element]]s, including [[helium]], [[oxygen]], [[nitrogen]], [[neon]] and [[argon]], have been found in the nebula with a roughly uniform concentration along the nebula.<ref>Corradi, R., Perinotto, M., Schwarz, H. and Claeskens, J. (1997). The chemical structure of bipolar planetary nebulae. I. IC 4406. ''Astronomy and Astrophysics'', 322, pp.975-981. [http://adsabs.harvard.edu/abs/1997A%26A...322..975C Online]</ref> The nebula is believed to also possess a relatively [[density|dense]] [[torus]] at its [[equator]] like many other planetary nebulae.<ref>Sahai, R., Wootten, A., Schwarz, H. and Clegg, R. (1991). The bipolar planetary nebula IC 4406 - CO, optical and dust emission. ''Astronomy and Astrophysics'', 251(2), pp.560-574. [http://adsabs.harvard.edu/abs/1991A&A...251..560S Online]</ref> At the centre of the nebula is a [[white dwarf]] that is thought to have a temperature of some 80,000 kelvin.<ref name=arxiv/>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]