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Puck (moon)

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Puck
Puck as imaged by Voyager 2 in January 1986. The image is centered on Puck's south pole. Despite the low resolution, several craters have been identified, including Bogle on the upper right
Discovery[1]
Discovered byStephen P. Synnott / Voyager 2
Discovery dateDecember 30, 1985
Designations
Designation
Uranus XV
Pronunciation/ˈpʌk/[2]
AdjectivesPuckian[3]
Orbital characteristics[4]
Periapsis85995 km
Apoapsis86013 km
86004 km
Eccentricity0.0001
0.761833 d
8.21 km/s[a]
Inclination0.327° (to Uranus's equator)
Satellite ofUranus
Physical characteristics
Dimensions81 × 81 × 81 km[5]
81±2 km[5]
(8.2±0.4)×104 km2[a]
Volume2226100 km3 ± 7.8%[6]
Mass(2.0035±0.1568)×1018 kg[6]
Mean density
0.5–1.2 g/cm3[7]
0.9 g/cm3 (assumed)[6]
~0.020 m/s2[a]
~0.057 km/s[a]
presumed synchronous[8]
assumed zero
Albedo
19.75 ± 0.05[11]
7.04 ± 0.05[11]

Puck is the sixth-largest moon of Uranus, and its largest inner moon. It was discovered in December 1985 by the Voyager 2 spacecraft.[1] Following the convention of naming Uranus's moons after characters from Shakespeare's literary works, its name was taken from A Midsummer Night's Dream.

The orbit of Puck lies between the rings of Uranus and the first of Uranus's large moons, Miranda. Puck is approximately spherical in shape and has diameter of about 162 km (101 mi).[12] It has a dark, heavily cratered surface, which shows spectral signs of water ice.[13]

Discovery and naming

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Of the moons discovered by the Voyager 2 imaging team, only Puck was discovered early enough that the probe could be programmed to image it in some detail.[1] Puck was discovered from the images Voyager 2 took on 30 December 1985. It was given the temporary designation S/1985 U 1.[14]

The moon was later named after the character Puck who appears in Shakespeare's A Midsummer Night's Dream, a little sprite who travels around the globe at night with the fairies. In Celtic mythology and English folklore, a Puck is a mischievous sprite, imagined as an evil demon by Christians.[citation needed]

It is also designated Uranus XV.[15]

Physical characteristics

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Map of Puck

With a radius of about 81 km (50 mi),[12] Puck is the largest inner moon of Uranus, orbiting inside the orbit of Miranda. It is intermediate in size between Portia (the second-largest inner moon) and Miranda (the smallest of the five major moons). One of the images taken by Voyager 2 had high enough resolution to constrain its shape in all three dimensions, which revealed that Puck has a shape consistent within errors to being a sphere.[5] The ratio between its equatorial axes a/b is 0.93–1, and the polar axis c is at least 95% of b.[5]

Its surface is heavily cratered[16] and is grey in color.[12] There are three named craters on the surface of Puck, the largest being about 45 km (28 mi) in diameter.[1] It has a relatively dark geometric albedo in visible light of approximately 10%.[17] It is about 10[18] or 15%[8] brighter on its trailing hemisphere than its leading hemisphere. Observations with the Hubble Space Telescope and large terrestrial telescopes found water-ice absorption features in the spectrum of Puck.[17][13]

Puck's orbit is located between the rings of Uranus and Miranda. Its surface is coated with a dark material similar to that found in the main rings.[13] The dark material is probably made of rocks or radiation-processed organics; it is possible that material spiralling inwards from Uranus's μ ring coats Puck's leading hemisphere as well.[19]

Little is known about the internal structure of Puck. It is probably made of a mixture of water ice and rocks, and may have been collisionally disrupted and reaccreted as a rubble pile.[19] The presence of a 3.0 deep 3.0 micron feature attributed to the O-H stretching mode suggests that water ice or hydrated minerals are a common component on Puck's surface.[20] Puck, as well as the other inner satellites of Uranus, is darker than the average inner Neptunian satellite, which could be either due to a higher level of solar irradiation at Uranus as opposed to Neptune, or a distinct composition.[20] The absence of craters with bright rays implies that Puck is not differentiated, meaning that ice and non-ice components have not separated from each other into a core and mantle.[1]

Named features

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Puck has three craters named Bogle, Butz, and Lob, which are named after mischievous spirits from Scottish, German, and British folklore respectively. Details about these craters are currently unknown.

Named craters on Puck
CraterCoordinatesDiameter (km)Approval dateNamed afterRef
Bogle—~47 km[19]1988Bogle (Celtic)WGPSN
Butz——1988Butz (German)WGPSN
Lob——1988Lob (English)WGPSN

See also

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Notes

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  1. 1 2 3 4 Calculated on the basis of other parameters.
  2. ↑ For the leading and trailing hemispheres respectively.
  3. ↑ Measured at 0.55 μm.

References

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Citations

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  1. 1 2 3 4 5 Smith Soderblom et al. 1986.
  2. ↑ "Puck". Lexico UK English Dictionary. Oxford University Press. Archived from the original on March 2, 2020.
  3. ↑ Sedgwick (1999) Shakespeare and the young writer
  4. ↑ Jacobson & Park 2025.
  5. 1 2 3 4 Karkoschka, Voyager 2001, p. 74–75.
  6. 1 2 3 French et al. 2024.
  7. ↑ French & Showalter 2012.
  8. 1 2 French et al. 2017.
  9. ↑ Showalter & Lissauer 2006, Supporting Online Material, Table S2.
  10. ↑ Karkoschka, Hubble 2001, Table VII.
  11. 1 2 Karkoschka, Hubble 2001, Table IV.
  12. 1 2 3 Karkoschka, Voyager 2001.
  13. 1 2 3 Dumas Smith et al. 2003.
  14. ↑ IAUC 4159.
  15. ↑ USGS: Planet and Satellite Names and Discoverers.
  16. ↑ Thomas Veverka et al. 1987.
  17. 1 2 Karkoschka, Hubble 2001.
  18. ↑ Showalter & Lissauer 2006.
  19. 1 2 3 Cartwright, Beddingfield & Nordheim 2021.
  20. 1 2 Belyakov, Matthew; Davis, M. Ryleigh; Milby, Zachariah; Wong, Ian; Brown, Michael E. (2024-05-01). "JWST Spectrophotometry of the Small Satellites of Uranus and Neptune". The Planetary Science Journal. 5 (5): 119. arXiv:2404.06660. Bibcode:2024PSJ.....5..119B. doi:10.3847/PSJ/ad3d55. ISSN 2632-3338.

Sources

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