Moons of Uranus
The inner moons are small dark bodies that share common properties and origins with
William Herschel discovered the first two moons, Titania and Oberon, in 1787. The other three ellipsoidal moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda).[1] These five may be in hydrostatic equilibrium. The remaining moons were discovered after 1985, either during the Voyager 2 flyby mission or with the aid of advanced Earth-based telescopes.[2][3]
Discovery
The first two moons to be discovered were
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.[8][9] Decades later, the flyby of the Voyager 2 space probe in January 1986 led to the discovery of ten further inner moons.[2] Another satellite, Perdita, was discovered in 1999[10] by Erich Karkoschka after studying old Voyager photographs.[11]
Uranus was the last giant planet without any known
Spurious moons
After Herschel discovered
Discovery of outer planet moons
Graphs are unavailable due to technical issues. There is more info on Phabricator and on MediaWiki.org. |
Names
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 sylph Ariel and gnome 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.[18] It is uncertain if John Herschel was the originator of the names, or if it was instead William Lassell (who discovered Ariel and Umbriel) who chose the names and asked Herschel for permission.[19]
Subsequent names, rather than continuing the airy spirits theme (only
Some
Characteristics and groups
The Uranian satellite system is the least massive among those of the
Inner moons
As of 2024, Uranus is known to have 13 inner moons, whose orbits all lie inside that of Miranda.[12] The inner moons are classified into two groups based on similar orbital distances: these are the Portia group, which includes the six moons Bianca, Cressida, Desdemona, Juliet, Portia, and Rosalind; and the Belinda group, which includes the three moons Cupid, Belinda, and Perdita.[12][22] All of the inner moons are intimately connected with the rings of Uranus, which probably resulted from the fragmentation of one or several small inner moons.[23] The two innermost moons, Cordelia and Ophelia, are shepherds of Uranus's ε ring, whereas the small moon Mab is a source of Uranus's outermost μ ring.[12] There may be two additional small (2–7 km in radius) undiscovered shepherd moons located about 100 km exterior to Uranus's α and β rings.[24]
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%.[25] They are composed of water ice contaminated with a dark material, probably radiation-processed organics.[26]
The inner moons constantly
Large moons
All major moons comprise approximately equal amounts rock and ice, except Miranda, which is made primarily of ice.
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).[2] 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,[c] during the hemispheric summer. 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 during the hemispheric summer, moving to a position over the celestial equator during the Uranian equinox, and then invisible below the horizon during the hemispheric winter.
Irregular moons
Uranus's irregular moons range in size from 120 to 200 km (Sycorax) to under 10 km (S/2023 U 1).[43] Due to the small number of known Uranian irregular moons, it is not yet clear which of them belong to groups with similar orbital characteristics. The only known group among Uranus's irregular moons is the Caliban group, which is clustered at orbital distances between 6–7 million km (3.7–4.3 million mi) and inclinations between 141°–144°.[14] The Caliban group includes three retrograde moons, which are Caliban, S/2023 U 1, Stephano.[14]
The intermediate inclinations 60° < i < 140° are devoid of known moons due to the Kozai instability.[3] 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.[3] Margaret is the only known irregular prograde moon of Uranus, and it has one of the most eccentric orbits of any moon in the Solar System.
List
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. The inner and major moons all have prograde orbits. 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. The orbits and mean distances of the irregular moons are variable over short timescales due to frequent planetary and solar perturbations, therefore the listed orbital elements of all irregular moons are averaged over a 8,000-year numerical integration by Brozović and Jacobson (2009). These may differ from osculating orbital elements provided by other sources.[44] The orbital elements of major moons listed here are based on the epoch of 1 January 2000,[45] while orbital elements of irregular satellites are based on the epoch of 1 January 2020.[46]
Key | ||||
---|---|---|---|---|
Inner moons |
♠ Major moons |
† Ungrouped prograde irregular moons |
‡ Ungrouped retrograde irregular moons |
♦ Caliban group |
Label [d] |
Name | Pronunciation ( key )
|
Image | Abs. magn.[47] |
Diameter
(km)[e] |
Semi-major axis
(km)[g] |
Orbital period (d)[g][h] |
Eccentricity [g] |
Discovery year[50] |
Year announced | Discoverer [50] |
Group | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
VI | Cordelia | /kɔːrˈdiːliə/ | 10.3 | 40 ± 6 (50 × 36) |
≈ 3.4 | 49800 | +0.33457 | 0.2 | 0.000 | 1986 | 1986 | Terrile (Voyager 2) |
ε ring shepherd | |
VII | Ophelia | /oʊˈfiːliə/ | 10.2 | 43 ± 8 (54 × 38) |
≈ 4.2 | 53800 | +0.37686 | 0.1 | 0.011 | 1986 | 1986 | Terrile (Voyager 2) |
ε ring shepherd | |
VIII | Bianca | /biˈɑːŋkə/ | 9.8 | 51 ± 4 (64 × 46) |
≈ 6.9 | 59200 | +0.43501 | 0.1 | 0.001 | 1986 | 1986 | Smith (Voyager 2) |
Portia | |
IX | Cressida | /ˈkrɛsədə/ | 8.9 | 80 ± 4 (92 × 74) |
≈ 27 | 61800 | +0.46315 | 0.1 | 0.000 | 1986 | 1986 | Synnott (Voyager 2) |
Portia | |
X | Desdemona | /ˌdɛzdəˈmoʊnə/ | 9.3 | 64 ± 8 (90 × 54) |
≈ 14 | 62700 | +0.47323 | 0.1 | 0.000 | 1986 | 1986 | Synnott (Voyager 2) |
Portia | |
XI | Juliet | /ˈdʒuːliət/ | 8.5 | 94 ± 8 (150 × 74) |
≈ 43 | 64400 | +0.49348 | 0.0 | 0.001 | 1986 | 1986 | Synnott (Voyager 2) |
Portia | |
XII | Portia | /ˈpɔːrʃə/ | 7.7 | 135 ± 8 (156 × 126) |
≈ 130 | 66100 | +0.51320 | 0.0 | 0.000 | 1986 | 1986 | Synnott (Voyager 2) |
Portia | |
XIII | Rosalind | /ˈrɒzələnd/ | 9.1 | 72 ± 12 | ≈ 20 | 69900 | +0.55846 | 0.0 | 0.000 | 1986 | 1986 | Synnott (Voyager 2) |
Portia | |
XXVII | Cupid | /ˈkjuːpəd/ | 12.6 | ≈ 18 | ≈ 0.31 | 74400 | +0.61317 | 0.1 | 0.005 | 2003 | 2003 | Showalter and Lissauer |
Belinda | |
XIV | Belinda | /bəˈlɪndə/ | 8.8 | 90 ± 16 (128 × 64) |
≈ 38 | 75300 | +0.62353 | 0.0 | 0.000 | 1986 | 1986 | Synnott (Voyager 2) |
Belinda | |
XXV | Perdita | /ˈpɜːrdətə/ | 11.0 | 30 ± 6 | ≈ 1.4 | 76400 | +0.63841 | 0.0 | 0.002 | 1999 | 1999 | Karkoschka (Voyager 2) |
Belinda | |
XV | Puck | /ˈpʌk/ | 7.3 | 162 ± 4 | 191±64 | 86005 | +0.76148 | 0.3562 | 0.0002 | 1985 | 1986 | Synnott (Voyager 2) |
||
XXVI | Mab | /ˈmæb/ | 12.1 | ≈ 18 | ≈ 0.31 | 97700 | +0.92329 | 0.1 | 0.003 | 2003 | 2003 | Showalter and Lissauer |
μ ring source | |
V | Miranda♠ | /məˈrændə/ | 3.5 | 471.6 ± 1.4 (481 × 468 × 466) |
6293±300 | 129858 | +1.4138 | 4.4072 | 0.0014 | 1948 | 1948 | Kuiper | ||
I | Ariel♠ | /ˈɛəriɛl/ | 1.0 | 1157.8±1.2 (1162 × 1156 × 1155) |
123310±1800 | 190930 | +2.5207 | 0.0167 | 0.0012 | 1851 | 1851 | Lassell | ||
II | Umbriel♠ | /ˈʌmbriəl/ | 1.7 | 1169.4±5.6 | 128850±2250 | 265982 | +4.1445 | 0.0796 | 0.0039 | 1851 | 1851 | Lassell | ||
III | Titania♠ | /təˈtɑːniə/ | 0.8 | 1576.8±1.2 | 345500±5090 | 436282 | +8.7064 | 0.1129 | 0.0012 | 1787 | 1787 | Herschel | ||
IV | Oberon♠ | /ˈoʊbərɒn/ | 1.0 | 1522.8±5.2 | 311040±7490 | 583449 | +13.464 | 0.1478 | 0.0014 | 1787 | 1787 | Herschel | ||
XXII | Francisco‡ | /frænˈsɪskoʊ/ | 12.4 | ≈ 22 | ≈ 0.56 | 4275700 | −267.11 | 146.8 | 0.144 | 2001 | 2003 | Holman et al. | ||
XVI | Caliban♦ | /ˈkælɪbæn/ | 9.1 | 42+20 −12 |
≈ 3.9 | 7167000 | −579.76 | 141.4 | 0.200 | 1997 | 1997 | Gladman et al. | Caliban | |
XX | Stephano♦ | /ˈstɛfənoʊ/ | 9.7 | ≈ 32 | ≈ 1.7 | 7951400 | −677.55 | 143.6 | 0.235 | 1999 | 1999 | Gladman et al. | Caliban | |
S/2023 U 1♦ | 13.7 | ≈ 8 | ≈ 0.027 | 7976600 | −680.78 | 143.9 | 0.250 | 2023 | 2024 | Sheppard et al. | Caliban | |||
XXI | Trinculo‡ | /ˈtrɪŋkjʊloʊ/ | 12.7 | ≈ 18 | ≈ 0.31 | 8502600 | −749.40 | 167.1 | 0.220 | 2001 | 2002 | Holman et al. | ||
XVII | Sycorax‡ | /ˈsɪkəræks/ | 7.4 | 157+23 −15 |
≈ 200 | 12193200 | −1288.40 | 157.0 | 0.520 | 1997 | 1997 | Nicholson et al. |
||
XXIII | Margaret† | /ˈmɑːrɡərət/ | 12.7 | ≈ 20 | ≈ 0.42 | 14425000 | +1655.16 | 60.5 | 0.642 | 2003 | 2003 | Sheppard and Jewitt |
||
XVIII | Prospero‡ | /ˈprɒspəroʊ/ | 10.5 | ≈ 50 | ≈ 6.5 | 16221000 | −1979.41 | 149.4 | 0.441 | 1999 | 1999 | Holman et al. | ||
XIX | Setebos‡ | /ˈsɛtɛbʌs/ | 10.7 | ≈ 47 | ≈ 5.4 | 17519800 | −2224.94 | 153.9 | 0.579 | 1999 | 1999 | Kavelaars et al. | ||
XXIV | Ferdinand‡ | /ˈfɜːrdənænd/ | 12.5 | ≈ 21 | ≈ 0.48 | 20421400 | −2808.70 | 169.2 | 0.395 | 2001 | 2003 | Holman et al. |
See also
Notes
- ^ The mass of Triton is about 2.14 × 1022 kg,[20] whereas the combined mass of the Uranian moons is about 0.92 × 1022 kg.
- ^ Uranus mass of 8.681 × 1025 kg / Mass of Uranian moons of 0.93 × 1022 kg
- ^ The axial tilt of Uranus is 97°.[2]
- Roman numeral attributed to each moon in order of their discovery.[1]
- ^ 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.[21] The diameter of Titania is from Widemann, 2009.[42] The dimensions and radii of the inner moons are from Karkoschka, 2001,[11] except for Cupid and Mab, which were taken from Showalter, 2006.[12] The radii of outer moons except Sycorax and Caliban were taken from Sheppard's website.[43] The radii of Sycorax and Caliban are from Farkas-Takács et al., 2017.[48]
- ^ Masses of Puck, Miranda, Ariel, Umbriel, Titania, and Oberon were taken from Jacobson, 2023 as reported in French, 2024.[49] Masses of all other moons were calculated assuming a density of 1 g/cm3 and using given radii.
- ^ a b c d Mean orbits of irregular satellites are taken from JPL Small System Dynamics,[46] while mean orbits of the five major moons and Puck are taken from Jacobson (2014).[45]
- retrograde orbitaround Uranus (opposite to the planet's orbit).
- ^ For regular satellites, inclination measures the angle between the moon's orbital plane and the plane defined by Uranus's equator. For irregular satellites, inclination measures the angle between the moon's orbital plane and the ecliptic.
References
- ^ a b c "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. Retrieved 2006-08-06.
- ^ a b c d e f g
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. S2CID 5895824.
- ^ a b c d e f
Sheppard, S. S.; Jewitt, D.; Kleyna, J. (2005). "An Ultradeep Survey for Irregular Satellites of Uranus: Limits to Completeness". The Astronomical Journal. 129 (1): 518–525. S2CID 18688556.
- .
- ^ Lassell, W. (1851). "On the interior satellites of Uranus". Monthly Notices of the Royal Astronomical Society. 12: 15–17. .
- .
- ^
doi:10.1086/100198.
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Kuiper, G. P. (1949). "The Fifth Satellite of Uranus". Publications of the Astronomical Society of the Pacific. 61 (360): 129. S2CID 119916925.
- ^
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.
- ^
ISSN 0081-0304. Retrieved 2011-11-02.
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Showalter, Mark R.; Lissauer, Jack J. (2006-02-17). "The Second Ring-Moon System of Uranus: Discovery and Dynamics". Science. 311 (5763): 973–977. S2CID 13240973.
- ^ "MPEC 2024-D113 : S/2023 U 1". Minor Planet Electronic Circular. Minor Planet Center. 23 February 2024. Retrieved 23 February 2024.
- ^ a b c "New Uranus and Neptune Moons". Earth & Planetary Laboratory. Carnegie Institution for Science. 23 February 2024. Retrieved 23 February 2024.
- ^ "Gemini Observatory Archive Search - Program GN-2021B-DD-104". Gemini Observatory. Retrieved 23 February 2024.
- ^
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.
- ^ 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.
- Bibcode:1852AN.....34..325.
- ^ a b Paul, Richard (2014). "The Shakespearean Moons of Uranus". folger.edu. Folger Shakespeare Library. Retrieved 25 February 2024.
- ^
Tyler, G.L.; Sweetnam, D.L.; et al. (1989). "Voyager radio science observations of Neptune and Triton". Science. 246 (4936): 1466–73. S2CID 39920233.
- ^ a b c Thomas, P. C. (1988). "Radii, shapes, and topography of the satellites of Uranus from limb coordinates". Icarus. 73 (3): 427–441. .
- S2CID 249192192. 38.
- ^
S2CID 250909885.
- S2CID 85559054.
- ^ a b .
- ^
Dumas, Christophe; Smith, Bradford A.; Terrile, Richard J. (2003). "Hubble Space Telescope NICMOS Multiband Photometry of Proteus and Puck". doi:10.1086/375909.
- ^ Duncan, Martin J.; Lissauer, Jack J. (1997). "Orbital Stability of the Uranian Satellite System". Icarus. 125 (1): 1–12. .
- ^ "Uranus's colliding moons". astronomy.com. 2017. Archived from the original on 26 February 2021. Retrieved 23 September 2017.
- ^ S2CID 9708287.
- ^
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. doi:10.1086/116211.
- ^ Mousis, O. (2004). "Modeling the thermodynamical conditions in the Uranian subnebula – Implications for regular satellite composition". Astronomy & Astrophysics. 413: 373–380. .
- ISBN 0-521-34323-2.
- ISSN 0004-6361.
- ISSN 1538-3881.
- ^ a b c Hussmann, Hauke; Sohl, Frank; Spohn, Tilman (November 2006). "Subsurface oceans and deep interiors of medium-sized outer planet satellites and large trans-neptunian objects". .
- ^
Grundy, W. M.; Young, L. A.; Spencer, J. R.; Johnson, R. E.; Young, E. F.; Buie, M. W. (October 2006). "Distributions of H2O and CO2 ices on Ariel, Umbriel, Titania, and Oberon from IRTF/SpeX observations". Icarus. 184 (2): 543–555. S2CID 12105236.
- ^
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. doi:10.1029/97JE00802. Archived from the originalon 2008-03-02.
- ^
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. hdl:1721.1/57632.
- ^ Tittemore, W. C. (September 1990). "Tidal heating of Ariel". Icarus. 87 (1): 110–139. .
- hdl:1721.1/57632.
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- ^ doi:10.1016/j.icarus.2008.09.011. Archived from the original(PDF) on July 25, 2014. Retrieved September 4, 2015.
- ^ a b Sheppard, Scott S. "Moons of Uranus". Earth & Planets Laboratory. Carnegie Institution for Science. Retrieved 23 February 2024.
- .
- ^ S2CID 122457734. 76.
- ^ a b "Planetary Satellite Mean Elements". Jet Propulsion Laboratory. Retrieved 28 February 2024. Note: Orbital elements of regular satellites are with respect to the Laplace plane, while orbital elements of irregular satellites are with respect to the ecliptic. Inclinations greater than 90° are retrograde. Orbital periods of irregular satellites may not be consistent with their semi-major axes due to perturbations.
- ^ "Natural Satellites Ephemeris Service". IAU: Minor Planet Center. Retrieved 2011-01-08.
- ^
Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; et al. (September 2017). "Properties of the Irregular Satellite System around Uranus Inferred from K2, Herschel, and Spitzer Observations". The Astronomical Journal. 154 (3): 13. S2CID 118869078. 119.
- .
- ^ a b "Planetary Satellite Discovery Circumstances". JPL Solar System Dynamics. NASA. Retrieved 28 February 2024.
External links
- Scott S. Sheppard: Uranus Moons
- Simulation Showing the location of Uranus's Moons
- "Uranus: Moons". NASA's Solar System Exploration. Archived from the original on 21 October 2015. 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.
- Gazetteer of Planetary Nomenclature—Uranus (USGS)
- "Uranus Rings photos", James Webb Space Telescope, NASA, December 18, 2023, retrieved 19 December 2023