Editing Vela (constellation)

{{short description|Constellation in the southern celestial hemisphere}}
{{About|the stellar constellation|the satellite program|Vela (satellite)}}

{{Infobox constellation
| name = Vela
| abbreviation = Vel
| genitive = Velorum
| pronounce = {{IPAc-en|ˈ|v|iː|l|ə}},<br/>genitive {{IPAc-en|v|ᵻ|ˈ|l|oʊ|r|əm}}
| symbolism = the [[Sail]]s
| RA = {{RA|9}}
| dec= {{DEC|−50}}
| family = [[Heavenly Waters (astronomy)|Heavenly Waters]]
| quadrant = SQ2
| areatotal = 500
| arearank = 32nd
| numbermainstars = 5
| numberbfstars = 50
| numberstarsplanets = 7
| numberbrightstars = 5
| numbernearbystars = 3
| brighteststarname = [[Gamma Velorum|γ Vel]]
| starmagnitude = 1.75
| neareststarname = [[Luhman 16]]
| stardistancely = 6.6
| stardistancepc = 2.0
| numbermessierobjects = 0
| meteorshowers = [[Delta Velids]]<br />[[Gamma Velids]]<br />[[Puppid-velids]]
| bordering = [[Antlia]]<br />[[Pyxis]]<br />[[Puppis]]<br />[[Carina (constellation)|Carina]]<br />[[Centaurus]]
| latmax = [[30th parallel north|30]]
| latmin = [[South Pole|90]]
| month = March
| notes=
}}
'''Vela''' is a [[constellation]] in the southern sky, which contains the [[Vela Supercluster]]. Its name is [[Latin]] for the [[sail]]s of a ship, and it was originally part of a larger constellation, the ship ''[[Argo Navis]]'', which was later divided into three parts, the others being [[Carina (constellation)|Carina]] and [[Puppis]]. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star [[Gamma Velorum]], one component of which is the closest and brightest [[Wolf–Rayet star|Wolf-Rayet]] star in the sky. [[Delta Velorum|Delta]] and [[Kappa Velorum]], together with [[Epsilon Carinae|Epsilon]] and [[Iota Carinae]], form the [[asterism (astronomy)|asterism]] known as the [[False Cross]]. 1.95-magnitude Delta is actually a triple or quintuple star system.

==History==
[[Argo Navis]] was one of the 48 classical constellations listed by the 2nd-century astronomer [[Ptolemy]], and represented the ship ''[[Argo]]'', used by [[Jason]] and the [[Argonauts]] on their quest for the [[Golden Fleece]] in [[Greek mythology]]. German cartographer [[Johann Bayer]] depicted the constellation on his  ''[[Uranometria]]'' of 1603, and gave the stars [[Bayer designation]]s from Alpha to Omega. However, his chart was inaccurate as the constellation was not fully visible from the Northern Hemisphere.<ref name=wagman>{{cite book  | last = Wagman  | first = Morton  | year = 2003  | title = Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others  | publisher = The McDonald & Woodward Publishing Company  | location = Blacksburg, [[Virginia|VA]]  | isbn = 978-0-939923-78-6 |pages=83, 315–19}}</ref>

Argo was more accurately charted and subdivided in 1752 by the French astronomer [[Nicolas Louis de Lacaille]], forming Carina (the [[keel]]), Vela (the sails), and Puppis (the [[poop deck]]). Despite the division, Lacaille kept Argo's [[Bayer designation]]s. Therefore, Carina has the Alpha, Beta and Epsilon originally assigned to Argo Navis, while Vela's brightest stars are Gamma and Delta, Puppis has Zeta as its brightest star, and so on.<ref name=wagman/>

==Characteristics==
[[File:Constellation Vela.jpg|thumb|left|The constellation of Vela, the sails, as it can be seen by the naked eye]]

Vela is bordered by [[Antlia]] and [[Pyxis]] to the north, Puppis to the northwest, Carina to the south and southwest, and [[Centaurus]] to the east. Covering 500 square degrees, it ranks 32nd of the 88 [[modern constellations]] in size. The three-letter abbreviation for the constellation, as adopted by the [[International Astronomical Union]] in 1922, is "Vel".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris |author-link=Henry Norris Russell | title=The New International Symbols for the Constellations | journal=Popular Astronomy | volume=30 | page=469 | bibcode=1922PA.....30..469R | year=1922 }}</ref>

The official constellation boundaries, as set by [[Eugène Joseph Delporte|Eugène Delporte]] in 1930, are defined by a polygon of 14 segments. In the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|08|13.3}} and {{RA|11|05.5}}, while the [[declination]] coordinates are between −37.16° and −57.17°.<ref name="boundary">{{Cite journal | title=Vela, constellation boundary | journal=The Constellations | publisher=International Astronomical Union | url=https://www.iau.org/public/themes/constellations/#vel | access-date=6 October 2013 }}</ref>
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==Features==

===Stars===
{{see also|List of stars in Vela}}
The brightest star in the constellation, Gamma Velorum, is a complex multiple star system. The brighter component, known as Gamma<sup>2</sup> Velorum, shines as a blue-white star of apparent magnitude 1.83.<ref name=ducati>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|pages=0|last1=Ducati|first1=J. R.|year=2002}}</ref> It is a spectroscopic binary made up of two very hot blue stars orbiting each other every 78.5 days and separated by somewhere between 0.8 and 1.6 Astronomical Units (AU). The brighter component is a hot blue main-sequence star of spectral type O7.5 and is around 280,000 times as luminous,  is around 30 times as massive and is 17 times the diameter of the Sun with a surface temperature of 35,000 K. The second component is an extremely rare example of hot star known as a [[Wolf–Rayet star]], and is the closest and brightest example in the sky. It has a surface temperature of 57,000 and is around 170,000 times as luminous as the Sun, though it radiates most of its energy in the ultraviolet spectrum.<ref name=north>{{cite journal|bibcode=2007MNRAS.377..415N|title=Γ2 Velorum: Orbital solution and fundamental parameter determination with SUSI|journal=Monthly Notices of the Royal Astronomical Society|volume=377|pages=415–424|last1=North|first1=J. R.|last2=Tuthill|first2=P. G.|last3=Tango|first3=W. J.|last4=Davis|first4=J.|date=2007|issue=1|doi=10.1111/j.1365-2966.2007.11608.x|doi-access=free |arxiv = astro-ph/0702375 |s2cid=16425744}}</ref>  Gamma<sup>1</sup> is a blue-white star of spectral type B2III and apparent magnitude 4.3.<ref name=jeffries/>  The two pairs are separated by 41 arcseconds, easily separable in binoculars.<ref name=jeffries>{{Cite journal | doi = 10.1111/j.1365-2966.2008.14162.x| title = The stellar association around Gamma Velorum and its relationship with Vela OB2| year = 2009| last1 = Jeffries | first1 = R. D.| last2 = Naylor | first2 = T.| last3 = Walter | first3 = F. M.| last4 = Pozzo | first4 = M. P.| last5 = Devey | first5 = C. R.| journal = Monthly Notices of the Royal Astronomical Society| volume = 393| issue = 2| pages = 538| doi-access = free|arxiv = 0810.5320 |bibcode = 2009MNRAS.393..538J | s2cid = 17560818}}</ref>  Parallax measurements give a distance of 1,116 light-years,<ref name=hipparcos>{{citation | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}</ref> meaning that they are at least 12,000 AU apart.  Further afield are 7.3-magnitude Gamma Velorum C and 9.4-magnitude Gamma Velorum D, lying 62 and 93 arcseconds south-southeast from Gamma<sup>2</sup>.

[[File:The dusty ring around the aging double star IRAS 08544-4431.jpg|left|thumb|Dusty ring around double star [[IRAS 08544-4431]].<ref>{{cite web|title=Sharpest View Ever of Dusty Disc Around Aging Star|url=http://www.eso.org/public/news/eso1608/|access-date=23 March 2016}}</ref>]]

The next brightest star is [[Delta Velorum]] or Alsephina,<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=8 August 2018}}</ref> also a multiple star system and one of the brightest eclipsing binaries in the sky. Together with [[Kappa Velorum]] or Markeb,<ref name="IAU-LSN"/> [[Iota Carinae]] or Aspidiske<ref name="IAU-LSN"/> and [[Epsilon Carinae]] or Avior,<ref name="IAU-LSN"/> it forms the diamond-shaped [[asterism (astronomy)|asterism]] known as the [[False Cross]]—so called because it is sometimes mistaken for the [[Crux|Southern Cross]], causing errors in [[astronavigation]].<ref>{{cite book|last=Moore|first=Patrick|title=Patrick Moore's Astronomy: Teach Yourself|publisher=Hachette |year=2010|isbn=978-1-4441-2977-9|url=https://books.google.com/books?id=D7M0Rgc1ONAC&pg=PT127}}</ref> Appearing as a white star of magnitude 1.95,<ref>{{cite web |url =http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+74956 |title = V* Delta Velorum -- Eclipsing binary of Algol type (detached) |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 11 October 2013}}</ref> Delta is actually a triple or possibly quintuple star system located around 80 light-years from the [[Solar System]]. Delta A has a magnitude of 1.99 and is an [[eclipsing binary]] composed of two A-type white stars (Delta Aa and Ab) which orbit each other every  45.2 days and lie 0.5 AU from each other, with a resulting drop in magnitude of 0.4 when the dimmer one passes.in front of the brighter. Delta B is a 5.1 magnitude yellow G-class star of similar dimensions to the Sun which ranges between 26 and 72 AU away from the brighter pair, taking 142 years to complete a revolution. Further out still, at a distance of 1700 AU, are two red dwarfs of magnitudes 11 and 13. If they are part of the multiple system, they take 28000 years to complete an orbit.<ref name="kalerdelta">{{cite web|url=http://stars.astro.illinois.edu/sow/deltavel.html |title=Delta Velorum |last=Kaler|first=Jim|author-link= James B. Kaler |work=Stars|publisher=University of Illinois|access-date=11 October 2013}}</ref> Also called Markeb, Kappa appears as a blue-white star of spectral type B2IV-V and magnitude 2.47 but is in fact a spectroscopic binary.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Kappa+velorum&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Kappa Velorum - Spectroscopic binary |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 10 October 2013}}</ref> The two orbit around each other with a period of 116.65 days,<ref name=aaa424_727>{{citation | display-authors=1 | last1=Pourbaix | first1=D. | last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H. | last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I. | last6=Levato | first6=H. | last7=Morrell | first7=N. I. | last8=Torres | first8=G. | last9=Udry | first9=S. | title=S<sub>B</sub>9: The ninth catalogue of spectroscopic binary orbits | journal=Astronomy and Astrophysics | volume=424 | issue=2 | pages=727–732 |date=September 2004 | doi=10.1051/0004-6361:20041213 | bibcode=2004A&A...424..727P |arxiv = astro-ph/0406573 | s2cid=119387088 }}</ref> but the size, mass and nature of the companion are as yet unclear.<ref name="kalermarkeb">{{cite web|url=http://stars.astro.illinois.edu/sow/markeb.html |title=Markeb |last=Kaler|first=Jim|author-link= James B. Kaler |work=Stars|publisher=University of Illinois|access-date=11 October 2013}}</ref>

The orange-hued [[Lambda Velorum]], or Suhail,<ref name="IAU-LSN"/> is the third-brightest star in the constellation. A supergiant of spectral type K4Ib-II, it varies between magnitudes 2.14 and 2.3,<ref name=lambvar>{{cite web |url = http://www.aavso.org/vsx/index.php?view=detail.top&oid=37806 |title = Lambda Velorum |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 11 October 2013 |date = 25 September 2009}}</ref> and lies 545 light-years distant.<ref>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Lambda+velorum&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = V* Lambda Velorum -- Pulsating Variable Star|work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 10 October 2013}}</ref> It has around 11,000 times the luminosity, 9 to 12 times the mass and 207 times the diameter of the Sun.<ref name="kalersuhail">{{cite web|url=http://stars.astro.illinois.edu/sow/suhail.html |title=Suhail |last=Kaler|first=Jim|author-link= James B. Kaler |work=Stars|publisher=University of Illinois|access-date=10 October 2013}}</ref>

[[AH Velorum]] is a Cepheid variable located less than a degree to the northeast of Gamma.<ref name="motz"/> A yellow-white supergiant of spectral type F7Ib-II, it pulsates between magnitudes 5.5 and 5.89 over 4.2 days.<ref name=AHvar>{{cite web |url = http://www.aavso.org/vsx/index.php?view=detail.top&oid=37478 |title = AH Velorum |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 11 October 2013 |date = 4 January 2010}}</ref> Also lying close to Gamma,<ref name="moorebinocs">{{cite book|last=Moore|first=Patrick|title=Exploring the Night Sky with Binoculars|publisher=Cambridge University Press|location=Cambridge, United Kingdom|year=2010|pages=144|isbn=978-0-521-79390-2|url=https://books.google.com/books?id=Jvbtl2Vyxm4C&pg=PA144}}</ref> [[V Velorum]] is a Cepheid of spectral type F6-F9II ranging from magnitude 7.2 to 7.9 over 4.4 days.<ref name=vvar>{{cite web |url = http://www.aavso.org/vsx/index.php?view=detail.top&oid=37421 |title = V Velorum |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 11 October 2013 |date = 4 January 2010}}</ref> [[AI Velorum]] is located 2.8 degrees north-northeast of Gamma,<ref name="motz"/> a Delta Scuti variable of spectral type A2p-F2pIV/V that ranges between magnitudes 6.15 and 6.76 in around 2.7 hours.<ref name=AIvar>{{cite web |url = https://www.aavso.org/vsx/index.php?view=detail.top&oid=37479 |title = AI Velorum |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 10 August 2022 |date = 11 September 2011}}</ref>

[[V390 Velorum]] is an aged star that has been found to be surrounded by a dusty disk. An [[RV Tauri variable]], it has a spectral type of F3e and ranges between magnitudes 9.01 and 9.27 over nearly 95 days.<ref name=V390var>{{cite web |url =http://www.aavso.org/vsx/index.php?view=detail.top&oid=136435 |title = V0390 Velorum |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 11 October 2013 |date = 25 May 2011}}</ref>

[[Omicron Velorum]] is a blue-white subgiant of spectral type B3III-IV located around 495 light-years from the Solar System. A slowly pulsating B star, it ranges between magnitudes 3.57 and 3.63 over 2.8 days.<ref name=omvar>{{cite web |url = http://www.aavso.org/vsx/index.php?view=detail.top&oid=37807 |title = Omicron Velorum |publisher = American Association of Variable Star Observers |work = International Variable Star Index |access-date = 11 October 2013 |date = 10 February 2012}}</ref> It is the brightest star in, and gives its name to, the Omicron Velorum Cluster, also known as [[IC 2391]], an [[open cluster]] located around 500 light-years away.

Seven star systems have been found to have [[exoplanet|planets]]. [[HD 75289]] is a Sun-like star of spectral type G0V with a [[hot Jupiter]] planetary companion that takes only about 3.51 days to revolve at an [[orbital distance]] of 0.0482 [[Astronomical Unit|AU]]. [[WASP-19]] is a star of apparent magnitude 12.3 located 815 light-years away, which has a hot Jupiter-like planet that orbits every 0.7 days. [[HD 73526]] is a Sun-like star of spectral type G6V that has two planets around double the mass of Jupiter each with orbits of 187 and 377 days, respectively.

[[HD 85390]] is an orange dwarf of spectral type K1.5V lying around 111 light-years distant with a planet 42 times as massive as Earth orbiting every 788 days.

[[HD 93385]] is a Sun-like star of spectral type G2/G3V located around 138 light-years away that is orbited by two super-Earths with periods of 13 and 46 days and masses 8.3 and 10.1 times that of Earth, respectively.

===Brown dwarfs===
The discovery of a binary [[brown dwarf]] system named [[Luhman 16]] only 6.6 light-years away, the third-closest system to the Solar System, was announced on 11 March 2013.

===Deep-sky objects===
Of the [[deep-sky object]]s of interest in Vela is a [[planetary nebula]] known as [[NGC 3132]], nicknamed the 'Eight-Burst Nebula' or 'Southern Ring Nebula' (see accompanying photo). It lies on the border of the constellation with Antlia.<ref name="motz"/> [[NGC 2899]] is an unusual red-hued example. This constellation has 32 more planetary nebulae.

[[File:NGC 3132.jpg|250px|thumbnail|left|Deep-sky photograph of [[NGC 3132]], also known as the Eight-Burst or Southern Ring Nebula. © NASA.]]

The [[Gum Nebula]] is a faint [[emission nebula]], believed to be the remains of a million-year-old supernova. Within it lies the smaller and younger [[Vela Supernova Remnant]]. This is the [[nebula]] of a [[supernova]] explosion that is believed to have been visible from Earth around 10,000 years ago.  The remnant contains the [[Vela Pulsar]], the first [[pulsar]] to be identified optically. Nearby is [[NGC 2736]], also known as the Pencil Nebula.

[[HH-47]] is a [[Herbig-Haro Object]], a young star around 1,400 [[light-year]]s from the Sun that is ejecting material at tremendous speed (up to a million kilometres per hour) into its surrounds. This material glows as it hits surrounding gas.<ref>{{cite web|url=http://www.almaobservatory.org/en/press-room/press-releases/632-alma-takes-close-look-at-drama-of-starbirth|title=ALMA Takes Close Look at Drama of Starbirth|last=Foncea|first=Valeria|author2=Arce|author3=Héctor|date=20 August 2013|work=Atacama Large Millimeter/Submillimeter Array|access-date=11 October 2013|archive-url=https://web.archive.org/web/20130927154903/http://www.almaobservatory.org/en/press-room/press-releases/632-alma-takes-close-look-at-drama-of-starbirth|archive-date=27 September 2013|url-status=dead|df=dmy-all}}</ref>

[[NGC 2670]] is an [[open cluster]] located in Vela. It has an overall magnitude of 7.8 and is 3,200 light-years from Earth. The stars of NGC 2670, a Trumpler class II 2 p and Shapley class-d cluster, are in a conformation suggesting a bow and arrow. Its class indicates that it is a poor, loose cluster, though detached from the star field. It is somewhat concentrated at its center, and its less than 50 stars range moderately in brightness.{{sfn|Levy|2005|p=87}}

Located 2 degrees south of Gamma Velorum, [[NGC 2547]] is an open cluster containing around 50 stars of magnitudes 7 to 15.<ref name="motz">{{cite book|last=Motz|first=Lloyd|author2=Nathanson, Carol |title=The Constellations: An Enthusiast's Guide to the Night Sky|publisher=Aurum Press|location=London, United Kingdom|year=1991|pages=381–83|isbn=978-1-85410-088-7}}</ref>

[[NGC 3201]] is a [[globular cluster]] discovered by [[James Dunlop]] on May 28, 1826. Its stellar population is inhomogeneous, varying with distance from the core. The [[effective temperature]] of the stars shows an increase with greater distance, with the redder and cooler stars tending to be located closer to the core. As of 2010, is one of only two clusters (including [[Messier 4]]) that shows a definite inhomogeneous population.<ref name=aaa512_L6>{{citation | display-authors=1 | last1=Kravtsov | first1=V. | last2=Alcaíno | first2=G. | last3=Marconi | first3=G. | last4=Alvarado | first4=F. | title=Evidence of the inhomogeneity of the stellar population in the differentially reddened globular cluster NGC 3201 | journal=Astronomy and Astrophysics | volume=512 | page=L6 |date=March 2010 | doi=10.1051/0004-6361/200913749 | bibcode=2010A&A...512L...6K | postscript=. |arxiv = 1004.5583 | s2cid=118407774 }}</ref>

[[RCW 36]] is a star-forming region in Vela, and one of the nearest sites of massive star formation. This star-forming region has given rise to a cluster of several hundred young stars that power an HII region.<ref name="Feigelson2013">{{Cite journal | last1 = Feigelson | display-authors = etal | year=2013 | title = Overview of the Massive Young Star-Forming Complex Study in Infrared and X-Ray (MYStIX) Project | journal = The Astrophysical Journal Supplement Series | volume = 209 | issue = 2 | pages = 26 | doi=10.1088/0067-0049/209/2/26 | arxiv=1309.4483 | bibcode=2013ApJS..209...26F| s2cid = 56189137 }}</ref> The star-forming region lies in Clump 6 in the [[Vela Molecular Ridge]] Cloud C.<ref name="Yamaguchi1999">{{Cite journal | last1 = Yamaguchi | display-authors = etal | year=1999 | title = A Study of Dense Molecular Gas and Star Formation toward the Vela Molecular Ridge with NANTEN | journal = Publications of the Astronomical Society of Japan | volume = 51 | issue = 6 | pages = 775–790 | doi=10.1093/pasj/51.6.775 | bibcode=1999PASJ...51..775Y| doi-access = free }}</ref>

==References==
{{reflist}}
* {{citation |title = Deep Sky Objects |last = Levy |first = David H. |publisher = Prometheus Books |year = 2005 |isbn = 1-59102-361-0 |url-access = registration |url = https://archive.org/details/deepskyobjects00davi }}
* Ian Ridpath and Wil Tirion (2017). ''Stars and Planets Guide'', Collins, [[London]]. {{ISBN|978-0008239275}}. [[Princeton University Press]], Princeton. {{ISBN|978-0691177885}}.
* Richard Hinckley Allen, ''Star Names, Their Lore and Legend'', [[New York City|New York]], Dover, various dates.

==External links==
{{Commons and category|Vela|Vela (constellation)}}
* [http://www.ianridpath.com/startales/vela.html Star Tales – Vela]
* [http://astrojan.nhely.hu/vela.htm The clickable Vela]

{{Stars of Vela}}
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[[Category:Vela (constellation)| ]]
[[Category:Constellations]]
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[[Category:Constellations listed by Lacaille]]