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{{Infobox Planet
| name = Oberon
| alt_names = Uranus IV
| adjectives = Oberonian
| image = [[Image:Voyager 2 picture of Oberon.jpg|200px]]
| caption = The best Voyager 2 image of Oberon obtained on January 24, 1986
| bgcolour = #a0ffa0
| discovery = yes
| discoverer = [[William Herschel]]
| discovered = January 11, 1787<ref name=Herschel1/>
| semimajor = 583&nbsp;520 [[Kilometre|km]]<ref name=orbit/>
| eccentricity = 0.0014<ref name=orbit/>
| period = 13.463&nbsp;234 [[Day|d]]<ref name=orbit/>
| inclination = 0.058° (to Uranus's equator)<ref name=orbit/>
| satellite_of = [[Uranus]]
| physical_characteristics = yes
| mean_radius = {{nowrap|761.4 ± 2.6}} km (0.1194 Earths)<ref name=Thomas1988/>
| surface_area = {{nowrap|7 285 000}} [[Square kilometre|km²]]<ref group=note>Surface area derived from the radius ''r'': <math>4\pi r^2</math>'''.</ref>
| volume = {{nowrap|1 849 000 000}} [[Cubic kilometre|km³]]<ref group=note>Volume ''v'' derived from the radius ''r'': <math>4\pi r^3/3</math>'''.</ref>
| mass = {{nowrap|3.014 ± 0.075}}{{Esp|21}} [[Kilogram|kg]] (5.046{{Esp|−4}} Earths)<ref name=Jacobson1992/>
| density = {{nowrap|1.63 ± 0.05}} [[Gram|g]]/[[Cubic centimeter|cm³]]<ref name=Jacobson1992/>
| surface_grav = {{Gr|3.014|762}} [[Acceleration|m/s<sup>2</sup>]]<ref group=note>Surface gravity derived from the mass ''m'', the [[gravitational constant]] ''G'' and the radius ''r'': <math>Gm/r^2</math>.</ref>
| escape_velocity = {{V2|3.014|762}} km/s<ref group=note>Escape velocity derived from the mass ''m'', the [[gravitational constant]] ''G'' and the radius ''r'': {{math|{{radical|2Gm/r}}}}.</ref>
| rotation = presumed [[Synchronous rotation|synchronous]]<ref name=Smith1986/>
| albedo = 0.31 (geometrical),<br /> 0.14 (bond)<ref name=Karkoschka2001a/>
| magnitude = 14.1<ref name=Newton/>
| single_temperature = 70&ndash;80&nbsp;[[Kelvin|K]]<ref name=Grundy2006/>
|note=no
}}
'''Oberon''' ({{pronEng|ˈoʊbərɒn}}),<ref group=note>In US dictionary transcription, {{USdict|ō′·bər·ŏn}}.</ref> also designated '''Uranus IV''', is the outermost major [[Natural satellite|moon]] of the planet [[Uranus]]. It is the second largest and second most massive of Uranian moons, and the ninth most massive moon in the Solar System. Discovered by [[William Herschel]] in 1787, Oberon is named after a character in Shakespeare's ''[[A Midsummer Night's Dream]]''. Its orbit lies partially outside Uranus's [[magnetosphere]].

Oberon consists of approximately equal amounts of ice and [[rock (geology)|rock]], and is likely differentiated into a rocky [[core (geology)|core]] and an icy [[mantle (geology)|mantle]]. A layer of liquid water may be present at the core/mantle boundary. The surface of Oberon, which is dark and slightly red in color, appears to have been primarily shaped by asteroid and comet impacts. It is covered by numerous [[impact crater]]s reaching 210&nbsp;km in diameter. Oberon possesses a system of [[canyon]]s ([[Fault scarp|scarp]]s) formed as a result of the expansion of its interior during its early evolution. This moon probably formed from the [[accretion disk]] that surrounded Uranus just after the planet's formation.

As of 2008, the Uranian system has been studied up close only once: by the spacecraft ''[[Voyager 2]]'' in January 1986. It took several images of Oberon, which allowed mapping of about 40% of the moon’s surface.

==Discovery and naming==
Oberon was discovered by [[William Herschel]] on January 11, 1787; on the same day he discovered Uranus's largest moon, [[Titania (moon)|Titania]].<ref name=Herschel1/><ref name=Herschel2/> He later reported the discoveries of four more satellites,<ref name=Herschel3/> although they were subsequently revealed as spurious.<ref name=Struve1848/> For nearly fifty years following their discovery, Titania and Oberon would not be observed by any instrument other than William Herschel's,<ref name=Herschel4/> although the moon can be seen from [[Earth]] with a present-day high end amateur telescope.<ref name=Newton>{{cite book|url=http://books.google.ru/books?id=l2TNnHkdDpkC|publisher=Cambridge University Press|title=The guide to amateur astronomy|date=1995|last=Newton|first=Bill|coauthors=Teece, Philip|isbn=9780521444927|page=109}}</ref>

All of the moons of Uranus are named after characters created by [[William Shakespeare]] or [[Alexander Pope]]. The name Oberon was derived from [[Oberon (Fairy King)|Oberon]], the King of the Fairies in ''[[A Midsummer Night's Dream]]''.<ref name=Kuiper1949/> The names of all four satellites of Uranus then known were suggested by Herschel's son [[John Herschel|John]] in 1852, at the request of [[William Lassell]],<ref name=Lassell5/> who had discovered the other two moons, [[Ariel (moon)|Ariel]] and [[Umbriel (moon)|Umbriel]], the year before.<ref name=Lassell1851/> The adjectival form of the name is ''Oberonian,'' {{pron-en|ˌɒbəˈroʊniən}}.

Oberon was initially referred to as "the second satellite of Uranus", and in 1848 was given the designation '''{{nowrap|Uranus II}}''' by William Lassell,<ref name=Lassell2/> although he sometimes used William Herschel's numbering (where Titania and Oberon are II and IV).<ref name=Lassell3/> In 1851 Lassell eventually numbered all four known satellites in order of their distance from the planet by [[Roman numerals]], and since then Oberon has been designated '''{{nowrap|Uranus IV}}'''.<ref name=Lassell1851b/>

==Orbit==
Oberon orbits Uranus at the distance of about 584,000&nbsp;km, being the furthest from the planet among its five major moons.{{#tag:ref|The five major moons are [[Miranda (moon)|Miranda]], [[Ariel (moon)|Ariel]], [[Umbriel (moon)|Umbriel]], [[Titania (moon)|Titania]] and Oberon.|group=note}} Oberon's orbit has a small [[orbital eccentricity]] and [[orbital inclination|inclination]] (relative to the [[equator]] of Uranus).<ref name=orbit/> Its orbital period is around 13.5&nbsp;days, coincident with its [[rotational period]]. In other words, Oberon is a [[synchronous orbit|synchronous satellite]], [[tidally locked]], with one face always pointing toward the planet.<ref name=Smith1986/> Oberon spends a significant part of its orbit outside the Uranian [[magnetosphere]].<ref name=Ness1986/> As a result, its surface is directly struck by the [[solar wind]].<ref name=Grundy2006/> This is important, because the trailing hemispheres of satellites orbiting inside a magnetosphere are struck by the magnetospheric plasma, which co&ndash;rotates with the planet.<ref name=Ness1986/> This bombardment may lead to the darkening of the trailing hemispheres, which is actually observed for all Uranian moons except Oberon (see below).<ref name=Grundy2006/> Because Uranus orbits the Sun almost on its side, and its moons orbit in the planet's equatorial plane, they (including Oberon) are subject to an extreme seasonal cycle. Both northern and southern [[Sphere#Hemisphere|hemisphere]]s spend 42 years in a complete darkness, and another 42 years in continuous sunlight.<ref name=Grundy2006/> Once every 42 years, when Uranus has an [[equinox]] and its equatorial plane intersects the Earth, mutual [[occultation]]s of Uranus's moons become possible. One such event, which last for about six minutes, was observed on May 4, 2007, when Oberon occulted Umbriel.<ref name=Hidas2008/>

==Composition and internal structure==
Oberon is the largest and most massive of Uranian moons after [[Titania (moon)|Titania]], and the ninth most massive moon in the Solar System.{{#tag:ref|The eight moons more massive than Oberon are [[Ganymede (moon)|Ganymede]], [[Titan (moon)|Titan]], [[Callisto (moon)|Callisto]], [[Io (moon)|Io]], Earth's [[Moon]], [[Europa (moon)|Europa]], [[Triton (moon)|Triton]], and [[Titania (moon)|Titania]].<ref name=NASA/>|group=note}} Oberon's density of 1.63&nbsp;g/cm<sup>3</sup>,<ref name=Jacobson1992/> which is higher than the typical density of Saturn's satellites, indicates that it consists of roughly equal proportions of [[Ice|water ice]] and a dense non-ice component.<ref name=Hassmann2006/> The latter could include [[rock (geology)|rocks]] and heavy [[organic compound]]s. The presence of water ice is supported by [[spectroscopic]] observations, which have revealed [[crystalline]] water ice on the surface of the moon.<ref name=Grundy2006/> Water ice [[absorption band]]s are stronger on Oberon's trailing hemisphere than on the leading hemisphere. This is the opposite of what is observed on other Uranian moons, where the leading hemisphere exhibits stronger water ice signatures.<ref name=Grundy2006/> The cause of this asymmetry is not known, but it may be related to [[impact gardening]] (the creation of soil via impacts) of the surface, which is stronger on the leading hemisphere.<ref name=Grundy2006/> [[Meteorite impact]]s tend to sputter (knock out) ice from the surface, leaving dark non-ice material behind. While no other compounds have been identified on the surface, plausible candidates for this dark material include rocks, [[carbon dioxide]], various [[salt]]s and organic compounds.<ref name=Smith1986/><ref name=Grundy2006/>

Oberon may be differentiated into a rocky [[core (geology)|core]] surrounded by an icy [[mantle (geology)|mantle]].<ref name=Hassmann2006/> If this is the case, the radius of the core (480&nbsp;km) is about 63% of the radius of the moon, and its mass is around 54% of the moon’s mass&mdash;the parameters are dictated by moon's composition. The pressure in the center of Oberon is about 0.5&nbsp;[[GPa]] (5&nbsp;[[kbar]]).<ref name=Hassmann2006/> The current state of the icy mantle is unclear. If the ice contains enough ammonia or other [[antifreeze]], Oberon may possess a liquid ocean layer at the core-mantle boundary. The thickness of this ocean, if it exists, is up to 40&nbsp;km and its temperature is around 180&nbsp;K.<ref name=Hassmann2006/> However the internal structure of Oberon depends heavily on its thermal history, which is poorly known at present.

==Surface features and geology==
[[File:Oberon USGS.jpg|thumb|right|An artificial color image of Oberon. The large crater with the dark floor (right of center) is [[Hamlet (crater)|Hamlet]].]]
Oberon is the second-darkest large moon of Uranus after [[Umbriel (moon)|Umbriel]].<ref name=Karkoschka2001a/> Its surface shows a strong [[opposition surge]]: its reflectivity decreases from 31% at a phase angle of 0° ([[albedo|geometrical albedo]]) to 22% at an angle of about 1°. Oberon has a very low [[bond albedo]] of about 14%.<ref name=Karkoschka2001a/> Its surface is generally slightly red in color, except for fresh impact deposits, which are neutral or slightly blue.<ref name=Helfenstein1990/> The trailing and leading hemispheres are asymmetrical: the former is less red than the latter, because it contains less dark red material.<ref name=Bell1991/> The reddening of the surfaces may be a result of [[space weathering]] caused by bombardment of the surface by charged particles and [[micrometeorites]] over the age of the [[Solar System]].<ref name=Bell1991/>

Scientists have recognized two classes of geological feature on Oberon: [[Impact crater|craters]] and [[chasma]]ta (canyons).<ref name=Smith1986/> The ancient surface of Oberon is the most heavily cratered of all the Uranian moons, with a crater density approaching saturation—when the formation of new craters is balanced by destruction of old ones.{{#tag:ref|The high number of craters on Oberon means that it has the most ancient surface among Uranus's moons.<ref name=Plescia1987/>|group=note}}<ref name=Plescia1987/> The crater diameters range from a few kilometers at the low end to 206 kilometers for the largest known crater,<ref name=Plescia1987/> [[Hamlet (crater)|Hamlet]].<ref name=usgsHamlet/> Many large craters are surrounded by bright impact ejecta ([[rayed crater|rays]]) consisting of relatively fresh ice.<ref name=Smith1986/> The largest craters, Hamlet, Othello and Macbeth, have floors made of a very dark material deposited after their formation.<ref name=Plescia1987/> A peak with a height of about 11&nbsp;km was observed in some ''Voyager'' images near the south-eastern limb of Oberon,<ref name=Moore2004/> which may be the central peak of a large impact basin with a diameter of about 375&nbsp;km.<ref name=Moore2004/> Oberon's surface is intersected by a system of [[canyon]]s, which, however, are less widespread than those found on Titania.<ref name=Smith1986/> The canyons are probably [[normal fault]]s or [[Fault scarp|scarp]]s,{{#tag:ref|Some canyons on Oberon are [[grabens]].<ref name=Plescia1987/>|group=note}} which can be either old or fresh: the latter [[transect]] the bright deposits of some large craters, indicating that they formed later.<ref name=Croft1989/> The most prominent among Oberonian canyons is [[Mommur Chasma]].<ref name=Mommur>{{cite web|title=Oberon: Mommur|publisher=USGS Astrogeology|work=Gazetteer of Planetary Nomenclature|url=http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=64127|accessdate=2009-03-06}}</ref>

The geology of Oberon was influenced by two competing forces: [[impact crater]] formation and [[endogenic]] resurfacing.<ref name=Croft1989/> The former acted over the moon's entire history and is primarily responsible for its present-day appearance.<ref name=Plescia1987/> The latter processes were active for a period following the moon's formation. The endogenic processes were mainly [[tectonic]] in nature and led to the formation of the canyons, which are actually giant cracks in the ice crust.<ref name=Croft1989/> The canyons obliterated parts of the older surface.<ref name=Croft1989/> The cracking of the crust was caused by the expansion of Oberon by about 0.5%,<ref name=Croft1989/> which occurred in two phases corresponding to the old and young canyons.

The nature of the dark patches, which mainly occur on the leading hemisphere and inside craters, is not known. Some scientists hypothesized that they are of [[cryovolcano|cryovolcanic]] origin (analogs of [[Lunar maria]]),<ref name=Plescia1987/> while others think that the impacts excavated dark material buried beneath the pure ice ([[crust (geology)|crust]]).<ref name=Helfenstein1990/> In the latter case Oberon should be at least partially differentiated, with the ice crust lying atop of the non-differentiated interior.<ref name=Helfenstein1990/>
{| class="wikitable" style="width:70%; text-align:center;"
|+ Named surface features on Oberon<ref name=usgs/>
! Feature !! Named after !! Type !! Length (diameter), km !! Latitude,° !! Longitude,°
|-
| [[Mommur Chasma]] || [[Mommur]], [[English folklore]] || [[Chasma]]|| 537 || &minus;16.3 || 323.5
|- 
| Antony || [[Antony and Cleopatra|Mark Antony]]
|  rowspan ="9" | [[Impact crater|Crater]] || 47 || &minus;27.5 || 65.4
|- 
| Caesar || [[Julius Caesar (play)|Julius Caesar]] || 76 || &minus;26.6 || 61.1
|-
| Coriolanus || [[Coriolanus (play)|Coriolanus]] || 120 || &minus;11.4 || 345.2
|- 
| Falstaff || [[Falstaff]] || 124 || &minus;22.1 || 19.0
|-
| [[Hamlet (crater)|Hamlet]] || [[Hamlet]] || 206 || &minus;46.1 || 44.4
|- 
| Lear || [[King Lear]]  || 126 || &minus;5.4 || 31.5
|- 
| MacBeth || [[Macbeth]] || 203 || &minus;58.4 || 112.5
|- 
| Othello || [[Othello]] || 114 || &minus;66.0 || 42.9
|- 
| Romeo || [[Romeo and Juliet|Romeo]] || 159 || &minus;28.7 || 89.4         
|}

==Origin and evolution==
Oberon is thought to have formed from an [[accretion disc]] or subnebula; a disc of gas and dust that either existed around Uranus for some time after its formation or was created by the giant impact that most likely gave Uranus its large [[obliquity]].<ref name=Mousis2004/> The precise composition of the subnebula is not known; however, the relatively high density of Oberon and other Uranian moons compared to the [[moons of Saturn]] indicates that it may have been relatively water-poor.{{#tag:ref|For instance, [[Tethys (moon)|Tethys]], a Saturnian moon, has the density of 0.97&nbsp;g/cm<sup>3</sup>, which means that it contains more than 90% of water.<ref name=Grundy2006/>|group=note}}<ref name=Smith1986/> Significant amounts of [[nitrogen]] and [[carbon]] may have been present in the form of [[carbon monoxide]] and N<sub>2</sub> instead of [[ammonia]] and [[methane]].<ref name=Mousis2004/> The moons that formed in such a subnebula would contain less water ice (with CO and N<sub>2</sub> trapped as [[clathrate]]) and more rock, explaining the higher density.<ref name=Smith1986/>

Oberon's accretion probably lasted for several thousand years.<ref name=Mousis2004/> The impacts that accompanied accretion caused heating of the moon's outer layer.<ref name=Squyres1988/> The maximum temperature of around 230&nbsp;K was reached at the depth of about 60&nbsp;km.<ref name=Squyres1988/> After the end of formation, the subsurface layer cooled, while the interior of Oberon heated due to decay of [[radioactivity|radioactive elements]] present in its rocks.<ref name=Smith1986/> The cooling near-surface layer contracted, while the interior expanded. This caused strong [[extensional stress]]es in the moon's crust leading to cracking. The present-day system of canyons may be a result of this process, which lasted for about 200&nbsp;million years,<ref name=Hillier1991/> implying that any endogenous activity ceased billions years ago.<ref name=Smith1986/>

The initial [[accretion (astrophysics)|accretional heating]] together with continued decay of radioactive elements were probably strong enough to melt the ice if some antifreeze like ammonia (in the form of [[hydrate|ammonia hydrate]]) was present.<ref name=Hillier1991/> Further melting may have led to the separation of ice from rocks and formation of a rocky core surrounded by an icy mantle. A layer of liquid water (ocean) rich in dissolved ammonia may have formed at the core–mantle boundary.<ref name=Hassmann2006/> The [[eutectic temperature]] of this mixture is 176&nbsp;K.<ref name=Hassmann2006/> If the temperature dropped below this value the ocean would have frozen by now. The freezing of the water led to the expansion of the interior, which may have also been responsible for the formation of canyons.<ref name=Plescia1987/> Still, the present knowledge of the evolution of Oberon is very limited.

==Exploration==
{{mainarticle|Exploration of Uranus}}
So far the only close-up images of Oberon have been from the ''[[Voyager 2]]'' probe, which photographed the moon during its flyby of Uranus in January 1986. Since the closest distance between Voyager 2 and Oberon was only 470,600&nbsp;km,<ref name=Stone1987/> the best images of this moon have spatial resolution of about 6&nbsp;km.<ref name=Plescia1987/> The images cover about 40% of the surface, but only images for 25% of the surface have quality, which allows the [[geological mapping]]. At the time of the flyby the southern hemisphere of Oberon was pointed towards the [[Sun]], so the northern (dark) hemisphere could not be studied.<ref name=Smith1986/> No other spacecraft ever visited Uranus (and Oberon), and no mission to this planet is planned in the foreseeable future.

==See also==
* [[Moons of Uranus]]
* [[Uranus in fiction#Oberon|Oberon in fiction]]

==Notes==
{{reflist|group=note|2}}

==References==
{{Source list
|name1=Smith1986
|name2=Karkoschka2001a
|name3=Hassmann2006
|name4=Jacobson1992
|name5=Grundy2006
|name6=Squyres1988
|name7=Moore2004
|name8=Mousis2004
|name9=Croft1989
|name10=Herschel1
|ref10={{cite journal|last=Herschel|first=William, Sr.|title=An Account of the Discovery of Two Satellites Revolving Round the Georgian Planet|journal=Philosophical Transactions of the Royal Society of London|volume=77|pages=125–129|year=1787|url=http://www.jstor.org/pss/106717|doi=10.1098/rstl.1787.0016}}
}}
{{Source list
|name1=Herschel2
|ref1={{cite journal|last=Herschel|first=William, Sr.|title=On George's Planet and its satellites|journal=Philosophical Transactions of the Royal Society of London|volume=78|pages=364–378|year=1788|doi=10.1098/rstl.1788.0024|url=http://adsabs.harvard.edu/abs/1788RSPT...78..364H}}
|name2=Herschel3
|ref2={{cite journal|title=On the Discovery of Four Additional Satellites of the Georgium Sidus; The Retrograde Motion of Its Old Satellites Announced; And the Cause of Their Disappearance at Certain Distances from the Planet Explained|journal=Philosophical Transactions of the Royal Society of London|volume=88|pages=47–79|year=1798|doi=10.1098/rstl.1798.0005|author=Herschel, William|url=http://adsabs.harvard.edu/abs/1798RSPT...88...47H}}
|name3=Herschel4
|ref3={{cite journal|author=[[John Herschel|Herschel, John]]|url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1834MNRAS...3Q..35H&amp;db_key=AST&amp;data_type=HTML&amp;format=&amp;high=45eb6e10af10464|title=On the Satellites of Uranus|journal=Monthly Notices of the Royal Astronomical Society|volume=3|issue=5|year=1834|pages=35–36}}
|name4=Lassell1851
|name5=Lassell2
|ref5={{cite journal|author=Lassell, W.|url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1848MNRAS...8...43.&amp;db_key=AST&amp;data_type=HTML&amp;format=&amp;high=45eb6e10af10464|title=Observations of Satellites of Uranus|journal=Monthly Notices of the Royal Astronomical Society|volume=8|issue=3|year=1848|pages=43–44}}
|name6=Helfenstein1990
|ref6={{cite journal|last=Helfenstein|first=P.|coauthors=Hiller, J.; Weitz, C. and Veverka, J.|title=Oberon: color photometry and its geological implications|year=1990|publisher=Lunar and Planetary Sciences Institute, Hoston|journal=Abstracts of the Lunar and Planetary Science Conference|volume=21|pages=489–490|url=http://adsabs.harvard.edu/abs/1990LPI....21..489H}}
|name7=Plescia1987
|name8=Kuiper1949
|name9=orbit
|ref9={{cite web|title=Planetary Satellite Mean Orbital Parameters|publisher=Jet Propulsion Laboratory, California Institute of Technology|url=http://ssd.jpl.nasa.gov/?sat_elem}}
|name10=Ness1986
}}
{{Source list
|name1=Lassell1851b
|name2=Struve1848
|ref2={{cite journal|last=Struve|first=O.|url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1848MNRAS...8...43.|title=Note on the Satellites of Uranus|journal=Monthly Notices of the Royal Astronomical Society|volume=8|issue=3|year=1848|pages=44–47}}
|name3=Lassell3
|ref3={{cite journal|last=Lassell|first=W.|url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1850MNRAS..10..135L|title=Bright Satellites of Uranus|journal=Monthly Notices of the Royal Astronomical Society|volume=10|issue=6|year=1850|pages=135}}
|name4=Lassell5
|ref4={{cite journal|title=Beobachtungen der Uranus-Satelliten|journal= Astronomische Nachrichten|volume=34|page=325|last=Lassell|first=W.|year=1852|url=http://adsabs.harvard.edu/abs/1852AN.....34..325.|accessdate=2008-12-18}}
|name5=Stone1987
|name6=Bell1991
|name7=Hidas2008
|ref7={{cite journal|last=Hidas|first=M.G.|coauthors=Christou, A.A.; Brown, T.M.|title=An observation of a mutual event between two satellites of Uranus|journal=Monthly Notices of the Royal Astronomical Society: Letters|year=2008|volume=384|pages=L38&ndash;L40|doi=10.1111/j.1745-3933.2007.00418.x|url=http://adsabs.harvard.edu/abs/2008MNRAS.384L..38H}}
|name8=NASA
|ref8={{cite web|url=http://ssd.jpl.nasa.gov/?sat_phys_par|title=Planetary Satellite Physical Parameters|publisher=Jet Propulsion Laboratory, NASA|accessdate=January 31, 2009}}
|name9=usgsHamlet
|ref9={{cite web|title=Oberon: Hamlet|publisher=USGS Astrogeology|work=Gazetteer of Planetary Nomenclature|url=http://planetarynames.wr.usgs.gov/jsp/FeatureNameDetail.jsp?feature=62509|accessdate=2009-01-06}}
|name10=usgs
|ref10={{cite web|title=Oberon Nomenclature Table Of Contents|publisher=USGS Astrogeology|work=Gazetteer of Planetary Nomenclature|url=http://planetarynames.wr.usgs.gov/jsp/FeatureTypes2.jsp?system=Uranus&body=Oberon&systemID=7&bodyID=34&sort=AName&show=Fname&show=Lat&show=Long&show=Diam&show=Stat&show=Orig|accessdate=2009-05-23}}
}}
{{Source list
|name1=Hillier1991
|name2=Thomas1988
}}
{{reflist|2}}

==External links==
*{{cite web|url=http://solarsystem.nasa.gov/planets/profile.cfm?Object=Ura_Oberon|publisher=[[NASA]]'s Solar System Exploration|title=Oberon profile|accessdate=May 21, 2009|date=1999|author=Hamilton, Calvin J. }}
*{{cite web|url=http://www.nineplanets.org/oberon.html|publisher=The Nine Planets Solar System Tour|title=Oberon profile|accessdate=March 6, 2009|date=December 22, 2004|author=Arnett, Bill}}
*{{cite web|url=http://www.nineplanets.org/see.html|publisher=The Nine Planets Solar System Tour|title=Seeing the Solar System|accessdate=March 6, 2009|date=November 17, 2004|author=Arnett, Bill}}

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