Moons of Uranus - wikipedia Moons of Uranus Uranus and its six largest moons compared at their proper relative sizes and relative positions. From left to right : Puck, Miranda, Ariel, Umbriel, Titania, and Oberon Uranus is the seventh planet of the Solar System ; it has 27 known moons, all of which are named after characters from the works of William Shakespeare and Alexander Pope. Uranus 's moons are divided into three groups : thirteen inner moons, five major moons, and nine irregular moons. The inner moons are small dark bodies that share common properties and origins with Uranus 's rings. The five major moons are massive enough to have reached hydrostatic equilibrium, and four of them show signs of internally driven processes such as canyon formation and volcanism on their surfaces. The largest of these five, Titania, is 1,578 km in diameter and the eighth - largest moon in the Solar System, and about one - twentieth the mass the Earth 's Moon. The orbits of the regular moons are nearly coplanar with Uranus 's equator, which is tilted 97.77 ° to its orbit. Uranus 's irregular moons have elliptical and strongly inclined ( mostly retrograde ) orbits at large distances from the planet. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the other three ellipsoidal moons were discovered in 1851 by William Lassell ( Ariel and Umbriel ) and in 1948 by Gerard Kuiper ( Miranda ). These five have planetary mass, and so would be considered ( dwarf ) planets if they were in direct orbit about the Sun. The remaining moons were discovered after 1985, either during the Voyager 2 flyby mission or with the aid of advanced Earth - based telescopes. Contents 1 Discovery 1.1 Spurious moons 2 Names 3 Characteristics and groups 3.1 Inner moons 3.2 Large moons 3.3 Irregular moons 4 List 5 Notes 6 References 7 External links Discovery The first two moons to be discovered were Titania and Oberon, which were spotted by Sir William Herschel on January 11, 1787, six years after he had discovered the planet itself. Later, Herschel thought he had discovered up to six moons ( see below ) and perhaps even a ring. For nearly 50 years, Herschel 's instrument was the only one with which the moons had been seen. In the 1840s, better instruments and a more favorable position of Uranus in the sky led to sporadic indications of satellites additional to Titania and Oberon. Eventually, the next two moons, Ariel and Umbriel, were discovered by William Lassell in 1851. The Roman numbering scheme of Uranus 's moons was in a state of flux for a considerable time, and publications hesitated between Herschel 's designations ( where Titania and Oberon are Uranus II and IV ) and William Lassell 's ( where they are sometimes I and II ). With the confirmation of Ariel and Umbriel, Lassell numbered the moons I through IV from Uranus outward, and this finally stuck. In 1852, Herschel 's son John Herschel gave the four then - known moons their names. No other discoveries were made for almost another century. In 1948, Gerard Kuiper at the McDonald Observatory discovered the smallest and the last of the five large, spherical moons, Miranda. Decades later, the flyby of the Voyager 2 space probe in January 1986 led to the discovery of ten further inner moons. Another satellite, Perdita, was discovered in 1999 after studying old Voyager photographs. Uranus was the last giant planet without any known irregular moons, but since 1997 nine distant irregular moons have been identified using ground - based telescopes. Two more small inner moons, Cupid and Mab, were discovered using the Hubble Space Telescope in 2003. As of 2016, the moon Margaret was the last Uranian moon discovered, and its characteristics were published in October 2003. The number of moons known for each of the four outer planets up to July 2018. Uranus currently has 27 known satellites. Spurious moons After Herschel discovered Titania and Oberon on January 11, 1787, he subsequently believed that he had observed four other moons : two on January 18 and February 9, 1790, and two more on February 28 and March 26, 1794. It was thus believed for many decades thereafter that Uranus had a system of six satellites, though the four latter moons were never confirmed by any other astronomer. Lassell 's observations of 1851, in which he discovered Ariel and Umbriel, however, failed to support Herschel 's observations ; Ariel and Umbriel, which Herschel certainly ought to have seen if he had seen any satellites beside Titania and Oberon, did not correspond to any of Herschel 's four additional satellites in orbital characteristics. Herschel 's four spurious satellites were thought to have sidereal periods of 5.89 days ( interior to Titania ), 10.96 days ( between Titania and Oberon ), 38.08 days, and 107.69 days ( exterior to Oberon ). It was therefore concluded that Herschel 's four satellites were spurious, probably arising from the misidentification of faint stars in the vicinity of Uranus as satellites, and the credit for the discovery of Ariel and Umbriel was given to Lassell. Names Main article : Naming of moons See also : Name conflicts with minor planets Although the first two Uranian moons were discovered in 1787, they were not named until 1852, a year after two more moons had been discovered. The responsibility for naming was taken by John Herschel, son of the discoverer of Uranus. Herschel, instead of assigning names from Greek mythology, named the moons after magical spirits in English literature : the fairies Oberon and Titania from William Shakespeare 's A Midsummer Night 's Dream, and the sylphs Ariel and Umbriel from Alexander Pope 's The Rape of the Lock ( Ariel is also a sprite in Shakespeare 's The Tempest ). The reasoning was presumably that Uranus, as god of the sky and air, would be attended by spirits of the air. Subsequent names, rather than continuing the airy spirits theme ( only Puck and Mab continued the trend ), have focused on Herschel 's source material. In 1949, the fifth moon, Miranda, was named by its discoverer Gerard Kuiper after a thoroughly mortal character in Shakespeare 's The Tempest. The current IAU practice is to name moons after characters from Shakespeare 's plays and The Rape of the Lock ( although at present only Ariel, Umbriel, and Belinda have names drawn from the latter ; all the rest are from Shakespeare ). At first, the outermost moons were all named after characters from one play, The Tempest ; but with Margaret being named from Much Ado About Nothing that trend has ended. The relative masses of the Uranian moons. The five rounded moons vary from Miranda at 0.7 % to Titania at almost 40 % of the total mass. The other moons collectively constitute 0.1 %, and are barely visible at this scale. The Rape of the Lock ( a poem by Alexander Pope ) : Ariel, Umbriel, Belinda Plays by William Shakespeare : A Midsummer Night 's Dream : Titania, Oberon, Puck The Tempest : ( Ariel ), Miranda, Caliban, Sycorax, Prospero, Setebos, Stephano, Trinculo, Francisco, Ferdinand King Lear : Cordelia Hamlet : Ophelia The Taming of the Shrew : Bianca Troilus and Cressida : Cressida Othello : Desdemona Romeo and Juliet : Juliet, Mab The Merchant of Venice : Portia As You Like It : Rosalind Much Ado About Nothing : Margaret The Winter 's Tale : Perdita Timon of Athens : Cupid Some asteroids share names with moons of Uranus : 171 Ophelia, 218 Bianca, 593 Titania, 666 Desdemona, 763 Cupido, and 2758 Cordelia. Characteristics and groups Schematic of the Uranian moon -- ring system The Uranian satellite system is the least massive among those of the giant planets. Indeed, the combined mass of the five major satellites is less than half that of Triton ( the seventh - largest moon in the Solar System ) alone. The largest of the satellites, Titania, has a radius of 788.9 km, or less than half that of the Moon, but slightly more than that of Rhea, the second - largest moon of Saturn, making Titania the eighth - largest moon in the Solar System. Uranus is about 10,000 times more massive than its moons. Inner moons See also : Inner moon and Rings of Uranus As of 2016, Uranus is known to have 13 inner moons. Their orbits lie inside that of Miranda. All inner moons are intimately connected to the rings of Uranus, which probably resulted from the fragmentation of one or several small inner moons. The two innermost moons ( Cordelia and Ophelia ) are as shepherds of Uranus 's ε ring, whereas the small moon Mab is a source of Uranus 's outermost μ ring. There may be two additional small ( 2 -- 7 km in radius ) undiscovered shepherd moons located about 100 km exterior to Uranus ' α and β rings. At 162 km, Puck is the largest of the inner moons of Uranus and the only one imaged by Voyager 2 in any detail. Puck and Mab are the two outermost inner satellites of Uranus. All inner moons are dark objects ; their geometrical albedo is less than 10 %. They are composed of water ice contaminated with a dark material -- probably radiation - processed organics. The small inner moons constantly perturb each other. The system is chaotic and apparently unstable. Simulations show that the moons may perturb each other into crossing orbits, which may eventually result in collisions between the moons. Desdemona may collide with either Cressida or Juliet within the next 100 million years. The five largest moons of Uranus compared at their proper relative sizes and brightnesses. From left to right ( in order of increasing distance from Uranus ) : Miranda, Ariel, Umbriel, Titania, and Oberon. Large moons Uranus has five major moons : Miranda, Ariel, Umbriel, Titania, and Oberon. They range in diameter from 472 km for Miranda to 1578 km for Titania. All these moons are relatively dark objects : their geometrical albedo varies between 30 and 50 %, whereas their Bond albedo is between 10 and 23 %. Umbriel is the darkest moon and Ariel the brightest. The masses of the moons range from 6.7 × 10 kg ( Miranda ) to 3.5 × 10 kg ( Titania ). For comparison, the Moon has a mass of 7.5 × 10 kg. The major moons of Uranus are thought to have formed in the accretion disc, which existed around Uranus for some time after its formation or resulted from a large impact suffered by Uranus early in its history. Artist 's conception of the Sun 's path in the summer sky of a major moon of Uranus ( which shares Uranus 's axial tilt ) All major moons comprise approximately equal amounts rock and ice, except Miranda, which is made primarily of ice. The ice component may include ammonia and carbon dioxide. Their surfaces are heavily cratered, though all of them ( except Umbriel ) show signs of endogenic resurfacing in the form of lineaments ( canyons ) and, in the case of Miranda, ovoid race - track like structures called coronae. Extensional processes associated with upwelling diapirs are likely responsible for the origin of the coronae. Ariel appears to have the youngest surface with the fewest impact craters, while Umbriel 's appears oldest. A past 3 : 1 orbital resonance between Miranda and Umbriel and a past 4 : 1 resonance between Ariel and Titania are thought to be responsible for the heating that caused substantial endogenic activity on Miranda and Ariel. One piece of evidence for such a past resonance is Miranda 's unusually high orbital inclination ( 4.34 ° ) for a body so close to the planet. The largest Uranian moons may be internally differentiated, with rocky cores at their centers surrounded by ice mantles. Titania and Oberon may harbor liquid water oceans at the core / mantle boundary. The major moons of Uranus are airless bodies. For instance, Titania was shown to possess no atmosphere at a pressure larger than 10 -- 20 nanobar. The path of the Sun in the local sky over the course of a local day during Uranus 's and its major moons ' summer solstice is quite different from that seen on most other Solar System worlds. The major moons have almost exactly the same rotational axial tilt as Uranus ( their axes are parallel to that of Uranus ). The Sun would appear to follow a circular path around Uranus 's celestial pole in the sky, at the closest about 7 degrees from it. Near the equator, it would be seen nearly due north or due south ( depending on the season ). At latitudes higher than 7 °, the Sun would trace a circular path about 15 degrees in diameter in the sky, and never set. Irregular moons of Uranus. The X axis is labeled in Gm ( million km ) and in the fraction of the Hill sphere 's radius. The eccentricity is represented by the yellow segments ( extending from the pericentre to the apocentre ) with the inclination represented on the Y axis. Irregular moons See also : Irregular moon As of 2005 Uranus is known to have nine irregular moons, which orbit it at a distance much greater than that of Oberon, the furthest of the large moons. All the irregular moons are probably captured objects that were trapped by Uranus soon after its formation. The diagram illustrates the orbits of those irregular moons discovered so far. The moons above the X axis are prograde, those beneath are retrograde. The radius of the Uranian Hill sphere is approximately 73 million km. Uranus 's irregular moons range in size from 120 -- 200 km ( Sycorax ) to about 20 km ( Trinculo ). Unlike Jupiter 's irregulars, Uranus 's show no correlation of axis with inclination. Instead, the retrograde moons can be divided into two groups based on axis / orbital eccentricity. The inner group includes those satellites closer to Uranus ( a < 0.15 r ) and moderately eccentric ( ~ 0.2 ), namely Francisco, Caliban, Stephano, and Trinculo. The outer group ( a > 0.15 r ) includes satellites with high eccentricity ( ~ 0.5 ) : Sycorax, Prospero, Setebos, and Ferdinand. The intermediate inclinations 60 ° < i < 140 ° are devoid of known moons due to the Kozai instability. In this instability region, solar perturbations at apoapse cause the moons to acquire large eccentricities that lead to collisions with inner satellites or ejection. The lifetime of moons in the instability region is from 10 million to a billion years. Margaret is the only known irregular prograde moon of Uranus, and it currently has the most eccentric orbit of any moon in the Solar System, though Neptune 's moon Nereid has a higher mean eccentricity. As of 2008, Margaret 's eccentricity is 0.7979. List Key Inner moons Major moons Irregular moons ( retrograde ) Irregular moon ( prograde ) The Uranian moons are listed here by orbital period, from shortest to longest. Moons massive enough for their surfaces to have collapsed into a spheroid are highlighted in light blue and bolded. Irregular moons with retrograde orbits are shown in dark grey. Margaret, the only known irregular moon of Uranus with a prograde orbit, is shown in light grey. Uranian moons Order Label Name Pronunciation ( key ) Image Diameter ( km ) Mass ( × 10 kg ) Semi-major axis ( km ) Orbital period ( d ) Inclination ( ° ) Eccentricity Discovery year Discoverer VI Cordelia / kɔːrˈdiːliə / 40 ± 6 ( 50 × 36 ) 0.044 7004497700000000000 ♠ 49 770 6999335034000000000 ♠ 0.335 034 6997147986467276599 ♠ 0.084 79 ° 6996259999999999999 ♠ 0.000 26 1986 Terrile ( Voyager 2 ) VII Ophelia / oʊ ˈfiːliə / 43 ± 8 ( 54 × 38 ) 0.053 7004537900000000000 ♠ 53 790 6999376400000000000 ♠ 0.376 400 6997180816110506612 ♠ 0.1036 ° 6997992000000000000 ♠ 0.009 92 1986 Terrile ( Voyager 2 ) VIII Bianca / biˈɑːŋkə / 51 ± 4 ( 64 × 46 ) 0.092 7004591700000000000 ♠ 59 170 6999434579000000000 ♠ 0.434 579 6997336848545634906 ♠ 0.193 ° 6996920000000000000 ♠ 0.000 92 1986 Smith ( Voyager 2 ) IX Cressida / ˈkrɛsɪdə / 80 ± 4 ( 92 × 74 ) 0.34 7004617800000000000 ♠ 61 780 6999463570000000000 ♠ 0.463 570 0.006 ° 6996360000000000000 ♠ 0.000 36 1986 Synnott ( Voyager 2 ) 5 X Desdemona / ˌdɛzdɪˈmoʊnə / 64 ± 8 ( 90 × 54 ) 0.18 7004626800000000000 ♠ 62 680 6999473650000000000 ♠ 0.473 650 6997194167879284369 ♠ 0.111 25 ° 6996129999999999999 ♠ 0.000 13 1986 Synnott ( Voyager 2 ) 6 XI Juliet / ˈdʒuːliət / 94 ± 8 ( 150 × 74 ) 0.56 7004643500000000000 ♠ 64 350 6999493065000000000 ♠ 0.493 065 6997113446401379631 ♠ 0.065 ° 6996660000000000000 ♠ 0.000 66 1986 Synnott ( Voyager 2 ) 7 XII Portia / ˈpɔːrʃə / 135 ± 8 ( 156 × 126 ) 1.70 7004660900000000000 ♠ 66 090 6999513196000000000 ♠ 0.513 196 0.059 ° 6995500000000000000 ♠ 0.000 05 1986 Synnott ( Voyager 2 ) 8 XIII Rosalind / ˈrɒzəlɪnd / 72 ± 12 0.25 7004699400000000000 ♠ 69 940 6999558459999999999 ♠ 0.558 460 0.279 ° 6996110000000000000 ♠ 0.000 11 1986 Synnott ( Voyager 2 ) 9 XXVII Cupid / ˈkjuːpɪd / ≈ 18 0.0038 7004748000000000000 ♠ 74 800 6999618000000000000 ♠ 0.618 0.1 ° 6997130000000000000 ♠ 0.0013 2003 Showalter and Lissauer 10 XIV Belinda / bɪˈlɪndə / 90 ± 16 ( 128 × 64 ) 0.49 7004752600000000000 ♠ 75 260 6999623527000000000 ♠ 0.623 527 0.031 ° 6995700000000000000 ♠ 0.000 07 1986 Synnott ( Voyager 2 ) 11 XXV Perdita / pərˈdiːtə / 30 ± 6 0.018 7004764000000000000 ♠ 76 400 6999638000000000000 ♠ 0.638 0.0 ° 6997119999999999999 ♠ 0.0012 1999 Karkoschka ( Voyager 2 ) 12 XV Puck / ˈpʌk / 162 ± 4 2.90 7004860100000000000 ♠ 86 010 6999761833000000000 ♠ 0.761 833 6997557109097236591 ♠ 0.3192 ° 6996120000000000000 ♠ 0.000 12 1985 Synnott ( Voyager 2 ) 13 XXVI Mab / ˈmæb / ≈ 25 0.01 7004977000000000000 ♠ 97 700 6999923000000000000 ♠ 0.923 6997233001455141243 ♠ 0.1335 ° 6997250000000000000 ♠ 0.0025 2003 Showalter and Lissauer 14 V Miranda / mɪˈrændə / 471.6 ± 1.4 ( 481 × 468 × 466 ) 7001659000000000000 ♠ 65.9 ± 7.5 7005129390000000000 ♠ 129 390 7000141347900000000 ♠ 1.413 479 4.232 ° 6997130000000000000 ♠ 0.0013 1948 Kuiper 15 Ariel / ˈɛəriəl / 7003115780000000000 ♠ 1157. 8 ± 1.2 ( 1162 × 1156 × 1155 ) 7003135300000000000 ♠ 1353 ± 120 7005191020000000000 ♠ 191 020 7000252037900000000 ♠ 2.520 379 0.260 ° 6997119999999999999 ♠ 0.0012 1851 Lassell 16 II Umbriel / ˈʌmbriəl / 7003116940000000000 ♠ 1169. 4 ± 5.6 7003117200000000000 ♠ 1172 ± 135 7005266300000000000 ♠ 266 300 4.144177 0.205 ° 6997390000000000000 ♠ 0.0039 1851 Lassell 17 III Titania / tɪˈteɪniə / 7003157680000000000 ♠ 1576. 8 ± 1.2 7003352700000000000 ♠ 3527 ± 90 7005435910000000000 ♠ 435 910 7000870587200000000 ♠ 8.705 872 0.340 ° 6997110000000000000 ♠ 0.0011 1787 Herschel 18 IV Oberon / ˈoʊbərɒn / 7003152280000000000 ♠ 1522. 8 ± 5.2 7003301400000000000 ♠ 3014 ± 75 7005583520000000000 ♠ 583 520 7001134632390000000 ♠ 13.463 239 0.058 ° 6997140000000000000 ♠ 0.0014 1787 Herschel 19 XXII Francisco / frænˈsɪskoʊ / ≈ 22 6997720000000000000 ♠ 0.0072 7006427600000000000 ♠ 4276000 − 266.56 147.459 ° 6999145900000000000 ♠ 0.1459 2003 Holman et al. 20 XVI Caliban / ˈkælɪbæn / ≈ 72 0.25 7006723000000000000 ♠ 7230000 − 579.50 139.885 ° 6999158700000000000 ♠ 0.1587 1997 Gladman et al. 21 XX Stephano / ˈstɛfənoʊ / ≈ 32 0.022 7006800200000000000 ♠ 8002000 − 676.50 141.873 ° 6999229200000000000 ♠ 0.2292 1999 Gladman et al. 22 XXI Trinculo / ˈtrɪŋkjʊloʊ / ≈ 18 6997390000000000000 ♠ 0.0039 7006857100000000000 ♠ 8571000 − 758.10 166.252 ° 6999220000000000000 ♠ 0.2200 Holman et al. 23 XVII Sycorax / ˈsɪkəræks / 7002165000000000000 ♠ 165 + 36 − 42 2.30 7007121790000000000 ♠ 12 179 000 − 1283.4 152.456 ° 6999522400000000000 ♠ 0.5224 1997 Nicholson et al. 24 XXIII Margaret / ˈmɑːrɡərɪt / ≈ 20 6997540000000000000 ♠ 0.0054 7007143450000000000 ♠ 14 345 000 1694.8 51.455 ° 6999660800000000000 ♠ 0.6608 2003 Sheppard and Jewitt 25 XVIII Prospero / ˈprɒspəroʊ / ≈ 50 0.085 7007164180000000000 ♠ 16 418 000 − 1992.8 146.017 ° 6999444800000000000 ♠ 0.4448 1999 Holman et al. 26 XIX Setebos / ˈsɛtɪbʌs / ≈ 48 0.075 7007174590000000000 ♠ 17 459 000 − 2202.3 145.883 ° 6999591400000000000 ♠ 0.5914 1999 Kavelaars et al. 27 XXIV Ferdinand / ˈfɜːrdɪnænd / ≈ 20 0.0054 7007209000000000000 ♠ 20 900 000 − 2823.4 167.346 ° 6999368200000000000 ♠ 0.3682 2003 Holman et al. Sources : NASA / NSSDC, Sheppard, et al. 2005. For the recently discovered outer irregular moons ( Francisco through Ferdinand ) the most accurate orbital data can be generated with the Natural Satellites Ephemeris Service. The irregulars are significantly perturbed by the Sun. Notes Jump up ^ The mass of Triton is about 2.14 × 10 kg, whereas the combined mass of the Uranian moons is about 0.92 × 10 kg. Jump up ^ Uranus mass of 8.681 × 10 kg / Mass of Uranian moons of 0.93 × 10 kg Jump up ^ The axial tilt of Uranus is 97 °. Jump up ^ Order refers to the position among other moons with respect to their average distance from Uranus. Jump up ^ Label refers to the Roman numeral attributed to each moon in order of their discovery. Jump up ^ Diameters with multiple entries such as `` 60 × 40 × 34 '' reflect that the body is not a perfect spheroid and that each of its dimensions have been measured well enough. The diameters and dimensions of Miranda, Ariel, Umbriel, and Oberon were taken from Thomas, 1988. The diameter of Titania is from Widemann, 2009. The dimensions and radii of the inner moons are from Karkoschka, 2001, except for Cupid and Mab, which were taken from Showalter, 2006. The radii of outer moons except Sycorax were taken from Sheppard, 2005. The diameter of Sycorax is from Lellouch, 2013. Jump up ^ Masses of Miranda, Ariel, Umbriel, Titania, and Oberon were taken from Jacobson, 1992. Masses of all other moons were calculated assuming a density of 1.3 g / cm and using given radii. Jump up ^ Negative orbital periods indicate a retrograde orbit around Uranus ( opposite to the planet 's rotation ). Jump up ^ Inclination measures the angle between the moon 's orbital plane and the plane defined by Uranus 's equator. ^ Jump up to : Detected in 2001, published in 2003. References ^ Jump up to : `` Planet and Satellite Names and Discoverers ''. Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. Retrieved 2006 - 08 - 06. ^ Jump up to : Smith, B.A. ; Soderblom, L.A. ; Beebe, A. ; Bliss, D. ; Boyce, J.M. ; Brahic, A. ; Briggs, G.A. ; Brown, R.H. ; Collins, S.A. ( 4 July 1986 ). `` Voyager 2 in the Uranian System : Imaging Science Results ''. Science. 233 ( 4759 ) : 43 -- 64. Bibcode : 1986Sci... 233... 43S. doi : 10.1126 / science. 233.4759. 43. PMID 17812889. ^ Jump up to : Sheppard, S.S. ; Jewitt, D. ; Kleyna, J. ( 2005 ). `` An Ultradeep Survey for Irregular Satellites of Uranus : Limits to Completeness ''. The Astronomical Journal. 129 : 518 -- 525. arXiv : astro - ph / 0410059. Bibcode : 2005AJ... 129... 518S. doi : 10.1086 / 426329. Jump up ^ Herschel, John ( 1834 ). `` On the Satellites of Uranus ''. Monthly Notices of the Royal Astronomical Society. 3 ( 5 ) : 35 -- 36. Bibcode : 1834MNRAS... 3... 35H. doi : 10.1093 / mnras / 3.5. 35. Jump up ^ Lassell, W. ( 1851 ). `` On the interior satellites of Uranus ''. Monthly Notices of the Royal Astronomical Society. 12 : 15 -- 17. Bibcode : 1851MNRAS... 12... 15L. doi : 10.1093 / mnras / 12.1. 15. Jump up ^ Lassell, W. ( 1848 ). `` Observations of Satellites of Uranus ''. Monthly Notices of the Royal Astronomical Society. 8 ( 3 ) : 43 -- 44. Bibcode : 1848MNRAS... 8... 43L. doi : 10.1093 / mnras / 8.3. 43. Jump up ^ Lassell, William ( December 1851 ). `` Letter from William Lassell, Esq., to the Editor ''. Astronomical Journal. 2 ( 33 ) : 70. Bibcode : 1851AJ... 2... 70L. doi : 10.1086 / 100198. ^ Jump up to : Kuiper, G.P. ( 1949 ). `` The Fifth Satellite of Uranus ''. Publications of the Astronomical Society of the Pacific. 61 ( 360 ) : 129. Bibcode : 1949PASP... 61... 129K. doi : 10.1086 / 126146. Jump up ^ Kaempffert, Waldemar ( December 26, 1948 ). `` Science in Review : Research Work in Astronomy and Cancer Lead Year 's List of Scientific Developments ''. The New York Times ( Late City ed. ). p. 87. ISSN 0362 - 4331. Jump up ^ Karkoschka, Erich ( May 18, 1999 ). `` S / 1986 U 10 ''. IAU Circular. 7171. ISSN 0081 - 0304. Retrieved 2011 - 11 - 02. ^ Jump up to : Karkoschka, Erich ( 2001 ). `` Voyager 's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites ''. Icarus. 151 ( 1 ) : 69 -- 77. Bibcode : 2001Icar... 151... 69K. doi : 10.1006 / icar. 2001.6597. ^ Jump up to : Showalter, Mark R. ; Lissauer, Jack J. ( 2006 - 02 - 17 ). `` The Second Ring - Moon System of Uranus : Discovery and Dynamics ''. Science. 311 ( 5763 ) : 973 -- 977. Bibcode : 2006Sci... 311... 973S. doi : 10.1126 / science. 1122882. PMID 16373533. Jump up ^ Sheppard, Scott S. ; Jewitt, D.C. ( 2003 - 10 - 09 ). `` S / 2003 U 3 ''. IAU Circular. 8217. ISSN 0081 - 0304. Retrieved 2011 - 11 - 02. Jump up ^ Hughes, D.W. ( 1994 ). `` The Historical Unravelling of the Diameters of the First Four Asteroids ''. R.A.S. Quarterly Journal. 35 ( 3 ) : 334 -- 344. Bibcode : 1994QJRAS... 35... 331H. Jump up ^ Denning, W.F. ( October 22, 1881 ). `` The centenary of the discovery of Uranus ''. Scientific American Supplement ( 303 ). Archived from the original on January 12, 2009. Jump up ^ William Lassell ( 1852 ). `` Beobachtungen der Uranus - Satelliten ''. Astronomische Nachrichten. 34 : 325. Bibcode : 1852AN... 34... 325. Retrieved 2008 - 12 - 18. Jump up ^ Tyler, G.L. ; Sweetnam, D.L. ; et al. ( 1989 ). `` Voyager radio science observations of Neptune and Triton ''. Science. 246 ( 4936 ) : 1466 -- 73. Bibcode : 1989Sci... 246.1466 T. doi : 10.1126 / science. 246.4936. 1466. PMID 17756001. ^ Jump up to : Thomas, P.C. ( 1988 ). `` Radii, shapes, and topography of the satellites of Uranus from limb coordinates ''. Icarus. 73 ( 3 ) : 427 -- 441. Bibcode : 1988Icar... 73... 427T. doi : 10.1016 / 0019 - 1035 ( 88 ) 90054 - 1. Jump up ^ Esposito, L.W. ( 2002 ). `` Planetary rings ''. Reports On Progress In Physics. 65 ( 12 ) : 1741 -- 1783. Bibcode : 2002RPPh... 65.1741 E. doi : 10.1088 / 0034 - 4885 / 65 / 12 / 201. Jump up ^ Chancia, R.O. ; Hedman, M.M. ( 2016 ). `` Are there moonlets near Uranus ' alpha and beta rings ? ''. The Astronomical Journal. arXiv : 1610.02376. Bibcode : 2016AJ... 152... 211C. doi : 10.3847 / 0004 - 6256 / 152 / 6 / 211. ^ Jump up to : Karkoschka, Erich ( 2001 ). `` Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope ''. Icarus. 151 ( 1 ) : 51 -- 68. Bibcode : 2001Icar... 151... 51K. doi : 10.1006 / icar. 2001.6596. Jump up ^ Dumas, Christophe ; Smith, Bradford A. ; Terrile, Richard J. ( 2003 ). `` Hubble Space Telescope NICMOS Multiband Photometry of Proteus and Puck ''. The Astronomical Journal. 126 ( 2 ) : 1080 -- 1085. Bibcode : 2003AJ... 126.1080 D. doi : 10.1086 / 375909. Jump up ^ Duncan, Martin J. ; Lissauer, Jack J. ( 1997 ). `` Orbital Stability of the Uranian Satellite System ''. Icarus. 125 ( 1 ) : 1 -- 12. Bibcode : 1997Icar... 125... 1D. doi : 10.1006 / icar. 1996.5568. ^ Jump up to : Jacobson, R.A. ; Campbell, J.K. ; Taylor, A.H. ; Synnott, S.P. ( June 1992 ). `` The masses of Uranus and its major satellites from Voyager tracking data and earth - based Uranian satellite data ''. The Astronomical Journal. 103 ( 6 ) : 2068 -- 2078. Bibcode : 1992AJ... 103.2068 J. doi : 10.1086 / 116211. Jump up ^ Mousis, O. ( 2004 ). `` Modeling the thermodynamical conditions in the Uranian subnebula -- Implications for regular satellite composition ''. Astronomy & Astrophysics. 413 : 373 -- 380. Bibcode : 2004A&A... 413... 373M. doi : 10.1051 / 0004 - 6361 : 20031515. Jump up ^ Hunt, Garry E. ; Patrick Moore ( 1989 ). Atlas of Uranus. Cambridge University Press. pp. 78 -- 85. ISBN 0 - 521 - 34323 - 2. ^ Jump up to : Hussmann, Hauke ; Sohl, Frank ; Spohn, Tilman ( November 2006 ). `` Subsurface oceans and deep interiors of medium - sized outer planet satellites and large trans - neptunian objects ''. Icarus. 185 ( 1 ) : 258 -- 273. Bibcode : 2006Icar... 185... 258H. doi : 10.1016 / j. icarus. 2006.06. 005. Jump up ^ Grundy, W.M. ; Young, L.A. ; Spencer, J.R. ; Johnson, R.E. ; Young, E.F. ; Buie, M.W. ( October 2006 ). `` Distributions of H O and CO ices on Ariel, Umbriel, Titania, and Oberon from IRTF / SpeX observations ''. Icarus. 184 ( 2 ) : 543 -- 555. arXiv : 0704.1525. Bibcode : 2006Icar... 184... 543G. doi : 10.1016 / j. icarus. 2006.04. 016. Jump up ^ Pappalardo, R.T. ; Reynolds, S.J. ; Greeley, R. ( 1996 ). `` Extensional tilt blocks on Miranda : Evidence for an upwelling origin of Arden Corona ''. Journal of Geophysical Research. 102 ( E6 ) : 13,369 -- 13,380. Bibcode : 1997JGR... 10213369P. doi : 10.1029 / 97JE00802. Jump up ^ Tittemore, William C. ; Wisdom, Jack ( June 1990 ). `` Tidal evolution of the Uranian satellites : III. Evolution through the Miranda - Umbriel 3 : 1, Miranda - Ariel 5 : 3, and Ariel - Umbriel 2 : 1 mean - motion commensurabilities ''. Icarus. 85 ( 2 ) : 394 -- 443. Bibcode : 1990Icar... 85... 394T. doi : 10.1016 / 0019 - 1035 ( 90 ) 90125 - S. Jump up ^ Tittemore, W.C. ( September 1990 ). `` Tidal heating of Ariel ''. Icarus. 87 ( 1 ) : 110 -- 139. Bibcode : 1990Icar... 87... 110T. doi : 10.1016 / 0019 - 1035 ( 90 ) 90024 - 4. Jump up ^ Tittemore, W.C. ; Wisdom, J. ( 1989 ). `` Tidal Evolution of the Uranian Satellites II. An Explanation of the Anomalously High Orbital Inclination of Miranda '' ( PDF ). Icarus. 78 ( 1 ) : 63 -- 89. Bibcode : 1989Icar... 78... 63T. doi : 10.1016 / 0019 - 1035 ( 89 ) 90070 - 5. Jump up ^ Malhotra, R. ; Dermott, S.F. ( 1990 ). `` The Role of Secondary Resonances in the Orbital History of Miranda ''. Icarus. 85 ( 2 ) : 444 -- 480. Bibcode : 1990Icar... 85... 444M. doi : 10.1016 / 0019 - 1035 ( 90 ) 90126 - T. ^ Jump up to : Widemann, T. ; Sicardy, B. ; Dusser, R. ; Martinez, C. ; Beisker, W. ; Bredner, E. ; Dunham, D. ; Maley, P. ; Lellouch, E. ; Arlot, J. - E. ; Berthier, J. ; Colas, F. ; Hubbard, W.B. ; Hill, R. ; Lecacheux, J. ; Lecampion, J. - F. ; Pau, S. ; Rapaport, M. ; Roques, F. ; Thuillot, W. ; Hills, C.R. ; Elliott, A.J. ; Miles, R. ; Platt, T. ; Cremaschini, C. ; Dubreuil, P. ; Cavadore, C. ; Demeautis, C. ; Henriquet, P. ; Labrevoir, O. ( February 2009 ). `` Titania 's radius and an upper limit on its atmosphere from the September 8, 2001 stellar occultation '' ( PDF ). Icarus. 199 ( 2 ) : 458 -- 476. Bibcode : 2009Icar... 199... 458W. doi : 10.1016 / j. icarus. 2008.09. 011. ^ Jump up to : `` Natural Satellites Ephemeris Service ''. IAU : Minor Planet Center. Retrieved 2011 - 01 - 08. Jump up ^ Lellouch, E. ; Santos - Sanz, P. ; Lacerda, P. ; Mommert, M. ; Duffard, R. ; Ortiz, J.L. ; Müller, T.G. ; Fornasier, S. ; Stansberry, J. ; Kiss, Cs. ; Vilenius, E. ; Mueller, M. ; Peixinho, N. ; Moreno, R. ; Groussin, O. ; Delsanti, A. ; Harris, A.W. ( September 2013 ). `` '' TNOs are Cool `` : A survey of the trans - Neptunian region. IX. Thermal properties of Kuiper belt objects and Centaurs from combined Herschel and Spitzer observations '' ( PDF ). Astronomy & Astrophysics. 557 : A60. Bibcode : 2013A&A... 557A... 60L. doi : 10.1051 / 0004 - 6361 / 201322047. Retrieved 7 November 2014. ^ Jump up to : Williams, Dr. David R. ( 2007 - 11 - 23 ). `` Uranian Satellite Fact Sheet ''. NASA ( National Space Science Data Center ). Retrieved 2008 - 12 - 20. Jump up ^ Jacobson, R.A. ( 1998 ). `` The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager 2 Observations ''. The Astronomical Journal. 115 ( 3 ) : 1195 -- 1199. Bibcode : 1998AJ... 115.1195 J. doi : 10.1086 / 300263. External links Wikimedia Commons has media related to Moons of Uranus. Simulation Showing the location of Uranus 's Moons `` Uranus : Moons ''. NASA 's Solar System Exploration. Retrieved 20 December 2008. `` NASA 's Hubble Discovers New Rings and Moons Around Uranus ''. Space Telescope Science Institute. 22 December 2005. Retrieved 20 December 2008. Sheppard, Scott. `` Uranus 's Known Satellites ''. Retrieved 20 December 2008. Gazetteer of Planetary Nomenclature -- Uranus ( USGS ) Moons of Uranus Generally listed in increasing distance from Uranus Inner Rings of Uranus Cordelia Ophelia Bianca Cressida Desdemona Juliet Portia Rosalind Cupid Belinda Perdita Puck Mab Major ( spheroid ) Miranda Ariel Umbriel Titania Oberon Outer ( irregular ) Francisco Caliban Stephano Trinculo Sycorax Margaret Prospero Setebos Ferdinand Geological features Arielian Kachina Chasmata Yangoor Mirandian Verona Rupes Oberonian Hamlet Mommur Chasma Puckian Titanian Gertrude Messina Chasmata Ursula Rousillon Rupes Umbrielian Wunda Vuver Skynd Uranus ( outline ) Geography Atmosphere Climate Dark Spot Magnetosphere Rings Moons Ariel Miranda Oberon Puck Titania Umbriel Astronomy Discovery William Herschel Gerard Kuiper James L. Elliot William Lassell General 15 Orionis Uranus - crossing minor planets Trojans 2011 QF 99 2014 YX 49 Exploration Past Voyager 2 ( 1986 flyby ) Proposals MUSE Oceanus ODINUS NASA Uranus orbiter and probe Uranus Pathfinder Related Fiction Portal Natural satellites of the Solar System Planetary satellites Terrestrial Martian Jovian Saturnian Uranian Neptunian Other satellites Minor - planet moons Plutonian Haumean Makemakean Eridian Largest satellites ( mean radius ≥ 100 km ) size Ganymede largest / 2634 km / 0.413 Earths Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Charon Umbriel Ariel Dione Tethys ( Dysnomia ) Enceladus Miranda Proteus Mimas ( Hi'iaka ) Nereid Hyperion Phoebe abc 's Ariel Callisto Charon Dione ( Dysnomia ) Enceladus Europa Ganymede ( Hi'iaka ) Hyperion Iapetus Io Mimas Miranda Moon Nereid Oberon Phoebe Proteus Rhea Tethys Titan Titania Triton Umbriel Discovery timeline Inner moons Irregular moons List Naming Regular moons Trojan moons NOTE : Italicized moons are not close to being in hydrostatic equilibrium ; ( bracketed ) moons may or may not be close to being in hydrostatic equilibrium. The Solar System The Sun Mercury Venus Earth Mars Ceres Jupiter Saturn Uranus Neptune Pluto Haumea Makemake Eris Planets and Dwarf planets Terrestrial planets Mercury Venus Earth Mars Giant planets Jupiter Saturn Uranus Neptune Dwarf planets Ceres Pluto Haumea Makemake Eris Rings Jovian Saturnian ( Rhean ) Charikloan Chironean Uranian Neptunian Haumean Moons Terrestrial Moon other near - Earth objects Martian Phobos Deimos Jovian Ganymede Callisto Io Europa all 79 Saturnian Titan Rhea Iapetus Dione Tethys Enceladus Mimas Hyperion Phoebe all 62 Uranian Titania Oberon Umbriel Ariel Miranda all 27 Neptunian Triton Proteus Nereid all 14 Plutonian Charon Nix Hydra Kerberos Styx Haumean Hiʻiaka Namaka Makemakean S / 2015 ( 136472 ) 1 Eridian Dysnomia Lists Solar System objects By size By discovery date Minor planets Gravitationally rounded objects Possible dwarf planets Natural satellites Comets Small Solar System bodies Meteoroids Minor planets moons Comets Damocloids Mercury - crossers Venus - crossers Venus trojans Near - Earth objects Earth - crossers Earth trojans Mars - crossers Mars trojans Asteroid belt Asteroids first discovered : Ceres Pallas Juno Vesta Families Notable asteroids Kirkwood gap Main - belt comets Jupiter trojans Jupiter - crossers Centaurs Saturn - crossers Uranus trojans Uranus - crossers Neptune trojans Cis - Neptunian objects Trans - Neptunian objects Neptune - crossers Plutoids Kuiper belt Plutinos Cubewanos Scattered disc Detached objects Sednoids Hills cloud Oort cloud Hypothetical objects Vulcan Vulcanoids Phaeton Planet V Theia Fifth giant Planets beyond Neptune Tyche Nemesis Planet Nine Exploration ( outline ) Discovery Astronomy Timeline Spaceflight Robotic spacecraft Human spaceflight List of crewed spacecraft Colonization List of probes Timeline Mercury Venus Moon Mars Ceres Asteroids Mining Comets Jupiter Saturn Uranus Neptune Pluto Deep space Outline of the Solar System Portals Solar System Astronomy Earth sciences Mars Jupiter Uranus Cosmology Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Virgo Supercluster → Laniakea Supercluster → Observable universe → Universe Each arrow ( → ) may be read as `` within '' or `` part of ''. 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Question: what is the number of moons on uranus
Answer: 27 known