View source for Red Spider Nebula

{{short description|Planetary nebula in the Milky Way}}
{{ Planetary nebula |
| image = [[File:The Red Spider Nebula, caught by Webb ESA513806.jpg|250px]]
| caption= The Red Spider Nebula imaged by the [[James Webb Space Telescope]]
| name = Red Spider Nebula
| type = Planetary
| epoch = [[J2000]]
| ra = {{RA|18|05|13.0977}}{{r|ned}}
| dec = {{DEC|-19|50|34.713}}{{r|ned}}
| dist_ly = ~[[1 E19 m|5000]]<ref name="Matsuuraetal2005"/>
| appmag_v = 13{{citation needed|date=June 2023}}
| size_v = {{Val|0.6|×|0.3|u=arcminute}}{{r|ned}}
| constellation = [[Sagittarius (constellation)|Sagittarius]]
| radius_pc = 1.1<ref name="Joel Kastner2025"/>
| absmag_v = -
| notes = hot white dwarf
| names = {{odlist | NGC= 6537 | name= ESO 590-PN 001 | 2MASS= J18051309-1950347}}{{r|ned}}
}}

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> It was discovered by [[Edward Charles Pickering]] on 15 July 1882.{{r|selig}}

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. Observations with [[Hubble Space Telescope|Hubble]] and JWST [[NIRCam]] showed hot (around 1000 K) circumstellar dust around the central star. The researchers propose that interactions between the progenitor star and a close companion are responsible for many features of NGC 6537. The central binary may be surrounded by a [[circumbinary disk]]. Non-detection in [[X-ray astronomy|X-rays]] suggests that the companion is less massive than the Sun.<ref name="Joel Kastner2025"/>

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" />

A research team studied the nebula with Hubble, [[Atacama Large Millimeter Array|ALMA]], [[Chandra X-ray Observatory|Chandra]] and JWST. The core of the nebula is shown to be consistent with a  highly asymmetric ring or irregular spiral with a radius of 5 [[arcseconds]] (0.04 [[parsec]]). The core is surrounded by an equatorial molecular torus with a deprojected radius of around 0.13 parsec and an inclination of 38°. The torus has an outflow velocity of 13 km/s and an age of around 10,000 years. Molecular [[hydrogen]] imaging showed the full extent of the polar lobes, showing that they are closed bubble-like structure with an extent of around 100 arcseconds (deprojected around 0.9 parsec). The lobes have an outflow velocity of around 300 km/s and a dynamical age of around 3700 years. The lobes have an S-shape in [[iron]] [Fe II] imaging, which is also seen in [[NGC 6302]]. This likely traces fast shocks from a collision between an active, collimated [[stellar wind]] with slower-moving material forming the polar lobe rims.<ref name="Joel Kastner2025"/>

== Gallery ==
<gallery>
Image:Bipolar planetary nebula NGC 6537.jpg|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> 
File:NGC6537.jpg|The Red Spider Nebula imaged by the [[Hubble Space Telescope]]
File:NGC 6537 JWST NIRCam.jpg|The Red Spider Nebula with JWST [[NIRCam]]. Iron is blue, molecular hydrogen is green and [[Hydrogen_spectral_series|Br-alpha]] is red.
File:NGC 6537 JWST NIRCam detail core.jpg|Central region of NGC 6537, revealing the central star as a red point inside the core.
</gallery>

== See also ==
* [[List of NGC objects (6001–7000)]]

== References ==
{{Reflist| refs=

<ref name=ned>{{cite web | website = NASA/IPAC Extragalactic Database | publisher = [[NASA]] and [[California Institute of Technology|Caltech]] | title = Results for object NGC 6537 | url = https://ned.ipac.caltech.edu/byname?objname=NGC+6537 | access-date = 31 October 2025}}</ref>

<ref name=selig>{{cite web | url = https://cseligman.com/text/atlas/ngc65.htm#6537 | title = New General Catalogue Objects: NGC 6537 | last = Seligman | first = Courtney | website = Celestial Atlas | access-date = 31 October 2025}}</ref>

<ref name="Joel Kastner2025">{{cite arXiv|last1=Kastner |first1=Joel |author2=Paula Moraga Baez |last3=Balick |first3=Bruce |author4=Rodolfo Montez Jr. |last5=Gieser |first5=Caroline |last6=Matsuura |first6=Mikako |last7=Nordhaus |first7=Jason |last8=Santander-Garcia |first8=Miguel |eprint=2509.11042|title=JWST/NIRCam imaging of the Bipolar Planetary Nebula NGC 6537: the (Infra)red Spider, Revealed |date=2025 |class=astro-ph.GA }}</ref>
}}

== 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}}
{{Stars of Sagittarius}}
{{Sky|18|05|13.0977|-|19|50|34.713}}
{{Catalogs|NGC=6537}}

[[Category:NGC objects|6537]]
[[Category:Sagittarius (constellation)]]
[[Category:Planetary nebulae]]
[[Category:Astronomical objects discovered in 1882|18820715]]
[[Category:ESO objects|590-PN 001]]