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Coordinates: Sky map 05h 41m 37.9s, −02° 15′ 52″
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{{Short description|Emission nebula in the constellation Orion}}
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{{Refimprove|date=December 2007}}
{{Cleanup rewrite|date=May 2009}}
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{{Infobox nebula
{{Infobox nebula
| name = [[New General Catalogue|NGC]] 2023
| name = NGC 2023
| image = Sunset Glow in Orion.jpg
| image = Barnard 33.jpg
| caption = NGC 2023 next to the [[Horsehead nebula]]
| caption = NGC 2023 picture created from multiple images taken with the Wide Field Camera of [[Hubble Space Telescope|Hubble]]’s Advanced Camera for Surveys.
| epoch = [[J2000]]
| type = reflection
| constellation = [[Orion (constellation)|Orion]]<ref name="ngc" />
| type2= [[emission nebula]]
| ra = {{RA|05|41|37.9}}<ref name="simbad" />
| epoch = [[J2000]]
| ra = {{RA|05|41|37.9}}<ref name="simbad" />
| dec = {{DEC|−02|15|52}}<ref name="simbad" />
| dec = {{DEC|−02|15|52}}<ref name="simbad" />
| dist_ly = {{Convert|400|pc|ly|order=flip|abbr=on|lk=on}}<ref name=López-García2013/>
| dist_ly = 1467.7
| appmag_v =
| type = reflection
| dist_pc = 450
| type2 = [[emission nebula]]
| appmag_v =
| size_v = 10′x10′<ref name="ngc" />
| size_v = 10'×10'<ref name="ngc" />
| radius_ly =
| constellation = [[Orion (constellation)|Orion]]<ref name="ngc" />
| radius_ly =
| absmag_v =
| absmag_v =
| notes =
| names = [[New General Catalogue|NGC]] 2023,<ref name="ngc" /> LBN 954, IRAS 05391-0217<ref name="simbad" />
| notes =
| names = NGC 2023,<ref name="ngc" /> LBN 954,<ref name="simbad" /> VDB 52, [XT95] 6, GN 05.39.1.02, RAFGL 806, [NYS99] C-23, IRAS 05391-0217, RX J0541.8-0217, [RK68] 38
}}
}}
'''NGC 2023''' (also known as '''LBN 954'''<ref name="simbad" />) is an [[Nebula|emission and reflection nebula]] located in the constellation of [[Orion (constellation)|Orion]]. It was discovered by [[William Herschel]] on 6 January 1785. It is around 10 x 10 arcmin.<ref name="ngc" />


'''NGC 2023''' is an [[Emission nebula|emission]] and [[reflection nebula]] in the [[celestial equator|equatorial]] [[constellation]] of [[Orion (constellation)|Orion]]. It was discovered by the [[Germany|German]]-born astronomer [[William Herschel]] on 6 January 1785. This reflection nebula is one of the largest in the sky,<ref name=scinews2019/> with a size of {{nowrap|10 × 10 arcminutes}}.<ref name="ngc" /> It is located at a distance of {{convert|400|pc|ly|order=flip|abbr=on}} from the [[Sun]], and is positioned {{Val|15|ul=arcminute|p=~}} to the northeast of the [[Horsehead Nebula]].<ref name=López-García2013/>
Regarding infrared wavelengths, it is a heavy source of [[fluorescent molecular hydrogen]] emission,<ref>http://adsabs.harvard.edu/full/1998PASA...15..194B</ref> and at 4 [[light-year]]s wide, it is one of the largest reflection nebulae in the sky. It is powered by an extremely hot [[Stellar classification#Class B|B-type star]] (B1.5), called [[HD 37903]], the most luminous member of a cluster of young Herbig–Haro objects that illuminate the outermost material in the [[Lynds 1630]] molecular cloud ([[Barnard 33]]) in Orion B.


This star-forming nebula forms part of the Orion B [[molecular cloud]],<ref name=López-García2013/> or [[Lynds 1630]], and is located in the northern section of this complex. In terms of [[stellar density]], it is the poorest of the four clusters embedded in the cloud complex, with only 21 embedded [[infrared]] sources.<ref name=Mookerjea2009/> The reflection nebula is illuminated by the [[Herbig Ae/Be star]] [[HD 37903]], which has a [[spectral class]] of about B2&nbsp;Ve.<ref name=Mookerjea2009/> The region around the central star is radiating fluorescent [[hydrogen line|molecular hydrogen emission]] at a near-[[infrared astronomy|infrared]] range.<ref name="1998Burton" /><ref name=Rouan1997/> Infrared emission of [[polycyclic aromatic hydrocarbons]] has been detected from the nebula's [[Cosmic dust|dust]].<ref name=Peeters2017/>
NGC 2023 forms a cavity in the surface of the cloud, some 450 [[parsecs]] from Earth. It produces a bright visual reflection nebula and an ultraviolet-excited [[photodissociation region]]. It is about a third of a [[degree (angle)|degree]] from the [[Horsehead Nebula]] <ref>http://www.fromquarkstoquasars.com/apotd-ngc-2023/</ref> and is often included (but not labeled) in images of that object.


==Gallery==
Additionally, one of the defining features of NGC 2023 — the overtly bright streak often seen in the upper-left hand corner — is not a true feature. Instead, the flare is an artifact generated by Hubble’s optics.<ref>http://www.spacetelescope.org/images/potw1130a/</ref>
<gallery>
The Birth of the Hunter.jpg|NGC 2023 taken with the [[Very Large Telescope|VLT]]'s FORS.
Sunset Glow in Orion.jpg|Southern detail of NGC 2023 ([[Hubble Space Telescope|HST]] [[Advanced Camera for Surveys|ACS]])
</gallery>


==References==
==References==
{{commonscat|NGC 2023}}
{{commons category|NGC 2023}}
{{Reflist|40em|refs=
{{Reflist|40em|refs=

<ref name="simbad">{{cite web|title=SIMBAD query result for NGC 2023|url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+2023|work=SIMBAD Astronomical Database|accessdate=2 August 2016}}</ref>
<ref name="ngc">{{Cite web|url = http://cseligman.com/text/atlas/ngc20.htm#2023|title = NGC Objects: NGC 2000 - 2049|date = |accessdate = |website = |publisher = |last = |first = }}</ref>
<ref name="simbad">{{cite simbad | title=NGC 2023 | accessdate=2020-08-28 }}</ref>

<ref name=Peeters2017>{{cite journal
| title=The PAH Emission Characteristics of the Reflection Nebula NGC 2023
| last1=Peeters | first1=Els | last2=Bauschlicher | first2=Charles W. Jr.
| last3=Allamandola | first3=Louis J. | last4=Tielens | first4=Alexander G. G. M.
| last5=Ricca | first5=Alessandra | last6=Wolfire | first6=Mark G.
| display-authors=1 | journal=The Astrophysical Journal
| volume=836 | issue=2 | id=198 | pages=40 | date=February 2017
| doi=10.3847/1538-4357/836/2/198 | arxiv=1701.06585
| bibcode=2017ApJ...836..198P | s2cid=119211134 | doi-access=free }}</ref>

<ref name=scinews2019>{{cite news
| website=Sci–News | date=May 14, 2019
| title=ESO's Very Large Telescope Snaps Beautiful Image of Reflection Nebula
| url=http://www.sci-news.com/astronomy/reflection-nebula-ngc-2023-07186.html
| access-date=2020-08-28 }}</ref>

<ref name=Rouan1997>{{cite journal
| title=The power of adaptive optics: a close look at a molecular cloud in NGC 2023
| display-authors=1 | last1=Rouan | first1=D.
| last2=Field | first2=D. | last3=Lemaire | first3=J. -L.
| last4=Lai | first4=O. | last5=Pineau des Forets | first5=G.
| last6=Falgarone | first6=E. | last7=Deltorn | first7=J. -M.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=284 | issue=2 | pages=395–400 | date=January 1997
| doi=10.1093/mnras/284.2.395 | bibcode=1997MNRAS.284..395R | doi-access=free }}</ref>

<ref name=Mookerjea2009>{{cite journal
| title=Young stars and protostellar cores near NGC 2023
| last1=Mookerjea | first1=B. | last2=Sandell | first2=G.
| last3=Jarrett | first3=T. H. | last4=McMullin | first4=J. P.
| display-authors=1 | journal=Astronomy and Astrophysics
| volume=507 | issue=3 | pages=1485–1502 | date=December 2009
| doi=10.1051/0004-6361/200912550 | arxiv=0909.2614
| bibcode=2009A&A...507.1485M | s2cid=10603379 }}</ref>

<ref name=López-García2013>{{cite journal
| title=A comprehensive study of NGC 2023 with XMM-Newton and Spitzer
| display-authors=1 | last1=López-García | first1=M. A.
| last2=López-Santiago | first2=J. | last3=Albacete-Colombo | first3=J. F.
| last4=Pérez-González | first4=P. G. | last5=de Castro | first5=E.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=429 | issue=1 | pages=775–791 | date=February 2013
| doi=10.1093/mnras/sts373 | arxiv=1211.2935
| bibcode=2013MNRAS.429..775L }}</ref>

<ref name="ngc">{{Cite web
| url=http://cseligman.com/text/atlas/ngc20.htm#2023
| first=Courtney | last=Seligman
| website=cseligman.com | access-date=2020-08-28
| title=NGC Objects: NGC 2000 - 2049 }}</ref>

<ref name="1998Burton">{{cite journal
| title=Near-IR Fluorescent Molecular Hydrogen Emission from NGC 2023
| last1=Burton | first1=Michael G. | last2=Howe | first2=J. E.
| last3=Geballe | first3=T. R. | last4=Brand | first4=P. W. J. L.
| display-authors=1 | bibcode=1998PASA...15..194B
| journal=[[Publications of the Astronomical Society of Australia]]
| volume=15 | issue=2 | pages=194–201 | year=1998
| doi=10.1071/AS98194 | doi-access=free }}</ref>

}}
}}


==External links==
==External links==
*{{cite web
| website=Hubble Space Telescope
| url=http://www.spacetelescope.org/images/potw1130a/
| title=Sunset glow in Orion
| publisher=[[NASA]] | date=25 July 2011}}
* [http://vizier.u-strasbg.fr/viz-bin/VizieR-S?NGC%202023 VizieR – NGC 2023]
* [http://vizier.u-strasbg.fr/viz-bin/VizieR-S?NGC%202023 VizieR – NGC 2023]
* [http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC%202023 NED – NGC 2023]
* [http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC%202023 NED – NGC 2023]{{WikiSky}}

*{{WikiSky}}
{{Catalogs|NGC=2023}}
{{Catalogs|NGC=2023}}
{{NGC objects:2000-2499}}
{{Sky|05|41|37.9|−|02|15|52|1}}
{{Sky|05|41|37.9|−|02|15|52|1}}
{{Ngc25}}


[[Category:Reflection nebulae]]
[[Category:Reflection nebulae]]
[[Category:Orion (constellation)]]
[[Category:Orion (constellation)]]
[[Category:Orion molecular cloud complex]]
[[Category:NGC objects|2023]]
[[Category:NGC objects|2023]]
[[Category:Discoveries by William Herschel]]

[[Category:Astronomical objects discovered in 1785]]

[[Category:Emission nebulae]]
{{nebula-stub}}

Revision as of 21:50, 27 March 2024

NGC 2023
Reflection nebula
emission nebula
NGC 2023 next to the Horsehead nebula
Observation data: J2000 epoch
Right ascension05h 41m 37.9s[1]
Declination−02° 15′ 52″[1]
Distance1,300 ly (400 pc)[2] ly
Apparent dimensions (V)10'×10'[3]
ConstellationOrion[3]
DesignationsNGC 2023,[3] LBN 954, IRAS 05391-0217[1]
See also: Lists of nebulae

NGC 2023 is an emission and reflection nebula in the equatorial constellation of Orion. It was discovered by the German-born astronomer William Herschel on 6 January 1785. This reflection nebula is one of the largest in the sky,[4] with a size of 10 × 10 arcminutes.[3] It is located at a distance of 1,300 ly (400 pc) from the Sun, and is positioned ~15 to the northeast of the Horsehead Nebula.[2]

This star-forming nebula forms part of the Orion B molecular cloud,[2] or Lynds 1630, and is located in the northern section of this complex. In terms of stellar density, it is the poorest of the four clusters embedded in the cloud complex, with only 21 embedded infrared sources.[5] The reflection nebula is illuminated by the Herbig Ae/Be star HD 37903, which has a spectral class of about B2 Ve.[5] The region around the central star is radiating fluorescent molecular hydrogen emission at a near-infrared range.[6][7] Infrared emission of polycyclic aromatic hydrocarbons has been detected from the nebula's dust.[8]

References

  1. ^ a b c "NGC 2023". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-28.
  2. ^ a b c López-García, M. A.; et al. (February 2013). "A comprehensive study of NGC 2023 with XMM-Newton and Spitzer". Monthly Notices of the Royal Astronomical Society. 429 (1): 775–791. arXiv:1211.2935. Bibcode:2013MNRAS.429..775L. doi:10.1093/mnras/sts373.
  3. ^ a b c d Seligman, Courtney. "NGC Objects: NGC 2000 - 2049". cseligman.com. Retrieved 2020-08-28.
  4. ^ "ESO's Very Large Telescope Snaps Beautiful Image of Reflection Nebula". Sci–News. May 14, 2019. Retrieved 2020-08-28.
  5. ^ a b Mookerjea, B.; et al. (December 2009). "Young stars and protostellar cores near NGC 2023". Astronomy and Astrophysics. 507 (3): 1485–1502. arXiv:0909.2614. Bibcode:2009A&A...507.1485M. doi:10.1051/0004-6361/200912550. S2CID 10603379.
  6. ^ Burton, Michael G.; et al. (1998). "Near-IR Fluorescent Molecular Hydrogen Emission from NGC 2023". Publications of the Astronomical Society of Australia. 15 (2): 194–201. Bibcode:1998PASA...15..194B. doi:10.1071/AS98194.
  7. ^ Rouan, D.; et al. (January 1997). "The power of adaptive optics: a close look at a molecular cloud in NGC 2023". Monthly Notices of the Royal Astronomical Society. 284 (2): 395–400. Bibcode:1997MNRAS.284..395R. doi:10.1093/mnras/284.2.395.
  8. ^ Peeters, Els; et al. (February 2017). "The PAH Emission Characteristics of the Reflection Nebula NGC 2023". The Astrophysical Journal. 836 (2): 40. arXiv:1701.06585. Bibcode:2017ApJ...836..198P. doi:10.3847/1538-4357/836/2/198. S2CID 119211134. 198.