View source for Red Spider Nebula

{{short description|Planetary nebula in the Milky Way}}
{{ Planetary nebula |
| image = [[Image:Bipolar planetary nebula NGC 6537.jpg|250px]]
| caption= Bipolar planetary nebula NGC 6537 taken with the New Technology Telescope at [[La Silla Observatory]].<ref>{{cite news|title=Bizarre Alignment of Planetary Nebulae|url=http://www.eso.org/public/news/eso1338/|access-date=6 September 2013|newspaper=ESO Press Release}}</ref> 
| credit = [[ESO]]
| name = Red Spider Nebula
| type = Planetary
| epoch = J2000.0
| ra = {{RA|18|05|13.1}}{{citation needed|date=June 2023}}
| dec = {{DEC|-19|50|35}}{{citation needed|date=June 2023}}
| dist_ly = ~[[1 E19 m|5000]]<ref name="Matsuuraetal2005"/>
| appmag_v = 13{{citation needed|date=June 2023}}
| size_v = 1.5 [[Minute of arc|arcmin]]{{citation needed|date=June 2023}}
| constellation = [[Sagittarius (constellation)|Sagittarius]]
| radius_ly = 1.1{{citation needed|date=June 2023}}
| absmag_v = -
| notes = hot white dwarf
| names = [[New General Catalogue|NGC]] 6537}}

The '''Red Spider Nebula''' (also catalogued as ''NGC 6537'') is a [[planetary nebula]] located near the heart of the Milky Way, in the northwest of <ref name="AAN">{{cite web |url=http://annesastronomynews.com/photo-gallery-ii/nebulae-clouds/the-red-spider-nebula-ngc-6537/ |title=The Red Spider Nebula, a planetary nebula in Sagittarius |date=2012-10-15 }}</ref> the constellation [[Sagittarius (constellation)|Sagittarius]].<ref name="APOD">{{Cite APOD |title=The Red Spider Planetary Nebula |date= 29 October 2012| access-date= 9 July 2014}}</ref> The nebula has a prominent two-lobed shape, possibly due to a binary companion or magnetic fields and has an S-shaped symmetry of the lobes – the lobes opposite each other appear similar. This is believed to be due to the presence of a companion to the central [[white dwarf]]. However, the gas walls of the two lobed structures are not at all smooth, but rather are rippled in a complex way.<ref name="AAN"/>

The central white dwarf, the remaining compact core of the original star, produces a powerful and hot (≈10,000 K) wind blowing with a speed of 300 kilometers per second, which has generated waves 100 billion kilometres high. The waves are generated by supersonic shocks formed when the local gas is compressed and heated in front of the rapidly expanding lobes. Atoms caught in the shocks radiate a visible light.<ref>{{cite web|title=Red Spider Nebula|url=http://www.astrophotolab.com/pr/n0109esa.htm|access-date=2015-01-27|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304075442/http://www.astrophotolab.com/pr/n0109esa.htm|url-status=dead}}</ref> These winds are what give this nebula its unique 'spider' shape and also contribute to the expansion of the nebula.<ref name="En-Sci">{{cite web|url=http://www.daviddarling.info/encyclopedia/R/Red_Spider_Nebula.html|title=Red Spider Nebula (NGC 6537)|publisher=Encyclopedia of Science, The Worlds of David Darling| access-date= 16 July 2014}}</ref>

The star at the center of the Red Spider Nebula is surrounded by a [[Circumstellar dust|dust shell]] making its exact properties hard to determine.  Its surface temperature is probably 150,000–250,000 K,<ref name="Matsuuraetal2005">{{Cite journal |title= The symmetric dust shell and the central star of the bipolar planetary nebula NGC 6537 |date= October 2005 |first= M. |last= Matsuura |journal= [[Monthly Notices of the Royal Astronomical Society]]|volume = 363|issue= 2 |pages= 628–640 |doi= 10.1111/j.1365-2966.2005.09464.x |doi-access= free |arxiv= astro-ph/0507641 |s2cid= 17118987 }}</ref> although a temperature of 340,000 K or even 500,000 K is not ruled out, making it among the hottest white dwarf stars known.

The Red Spider Nebula lies near the constellation of Sagittarius. Its distance has been variously estimated as 1,900 light-years<ref name="En-Sci" /><ref name="SurfingSag">{{cite web| url= http://www.spacetelescope.org/images/html/heic0109a.html| title= The Red Spider Nebula: Surfing in Sagittarius - not for the faint-hearted!| publisher= [[ESA]]/[[Hubble Space Telescope]]| date= 24 July 2001| access-date= 16 July 2014| url-status= dead| archive-url= https://web.archive.org/web/20090831103337/http://www.spacetelescope.org/images/html/heic0109a.html| archive-date= 31 August 2009}}</ref> or, more likely, 3,000–8,000 light-years.<ref name="Matsuuraetal2005" />

== References ==
{{Reflist}}
[[File:NGC6537.jpg|thumbnail|The Red Spider Nebula imaged by the [[Hubble Space Telescope]]]]

== External links ==
* {{commons category-inline}}
*[https://web.archive.org/web/20090831103337/http://www.spacetelescope.org/images/html/heic0109a.html Red Spider Nebula at ESA/Hubble]
*[https://web.archive.org/web/20010803033438/http://www.space.com/scienceastronomy/astronomy/red_spider_010724.html White dwarf sends ripples through Red Spider Nebula at Space.com]
*{{APOD |date=6 January 1998 |title=The Red Spider Planetary Nebula}}
*{{APOD |date=19 April 2017 |title=The Red Spider Planetary Nebula}}

{{NGC objects:6500-6999}}

[[Category:NGC objects]]
[[Category:Sagittarius (constellation)]]
[[Category:Planetary nebulae]]


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