Cressida (Moon)

Cressida
	Enhanced Voyager 2 image of Cressida
Discovery
Discovered by	Stephen P. Synnott / Voyager 2
Discovery date	January 9, 1986
Designations
Designation	Uranus IX
Pronunciation	/ˈkrɛsədə/
Named after	Χρησίδα
Adjectives	Cressidian /krɛˈsɪdiən/
Orbital characteristics
Mean orbit radius	61,766.730 ± 0.046 km
Eccentricity	0.00036 ± 0.00011
Orbital period	0.463569601 ± 0.000000013 d
Inclination	0.006 ± 0.040° (to Uranus' equator)
Satellite of	Uranus
Physical characteristics
Dimensions	92 × 74 × 74 km
Mean radius	39.8 ± 2 km
Surface area	~20,000 km2
Volume	~260,000 km3
Mass	2.5±0.4×1017 kg
Mean density	0.86±0.16 g/cm3
surface gravity	~0.013 m/s2
escape velocity	~0.034 km/s
Rotation period	synchronous
Axial tilt	zero
Physics	~64 K

Short description: Moon of Uranus

There is also an asteroid called 548 Kressida.

Cressida /ˈkrɛsədə/ is an inner satellite of Uranus. It was discovered from the images taken by Voyager 2 on 9 January 1986, and was given the temporary designation S/1986 U 3.^[8] It was named after Cressida, the Trojan daughter of Calchas, a tragic heroine who appears in William Shakespeare's play Troilus and Cressida (as well as in tales by Geoffrey Chaucer and others). It is also designated Uranus IX.^[9]

Cressida belongs to the Portia group of satellites, which includes Bianca, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda and Perdita.^[10] These satellites have similar orbits and photometric properties.^[10] Other than its orbit,^[3] radius of 41 km^[4] and geometric albedo of 0.08,^[10] virtually nothing is known about it.

In the Voyager 2 images Cressida appears as an elongated object, its major axis pointing towards Uranus. The ratio of axes of Cressida's prolate spheroid is 0.8 ± 0.3.^[4] Its surface is grey in color.^[4]

Cressida orbits close to a 3:2 resonance with the η ring, one of the rings of Uranus. Perturbations of the ring's shape provide a way to measure the mass of Cressida, which was found to be 2.5±0.4×10¹⁷ kg. Cressida is the only small satellite of Uranus for which the mass has been directly measured.^[7]

Cressida may collide with Desdemona within the next 100 million years.^[11]

References

Explanatory notes

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 Calculated on the basis of other parameters.

Citations

↑ Benjamin Smith (1903) The Century Dictionary and Cyclopedia
↑ Kellog (1995) Boccaccio's and Chaucer's Cressida
↑ ^3.0 ^3.1 ^3.2 ^3.3 ^3.4 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. doi:10.1086/300263. Bibcode: 1998AJ....115.1195J.
↑ ^4.0 ^4.1 ^4.2 ^4.3 ^4.4 ^4.5 ^4.6 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. doi:10.1006/icar.2001.6597. Bibcode: 2001Icar..151...69K.
↑ "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 24 October 2008. http://ssd.jpl.nasa.gov/?sat_phys_par.
↑ Williams, Dr. David R. (23 November 2007). "Uranian Satellite Fact Sheet". NASA (National Space Science Data Center). http://nssdc.gsfc.nasa.gov/planetary/factsheet/uraniansatfact.html.
↑ ^7.0 ^7.1 ^7.2 Chancia, Robert. A.; Hedman, Matthew M.; French, Richard G. (28 August 2017). "Weighing Uranus' moon Cressida with the η ring". The Astronomical Journal 154 (4): 153. doi:10.3847/1538-3881/aa880e. Bibcode: 2017AJ....154..153C.
↑ Smith, B. A. (January 16, 1986). "Satellites of Uranus". IAU Circular 4164. http://www.cbat.eps.harvard.edu/iauc/04100/04164.html#Item1. Retrieved 29 October 2011.
↑ "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. http://planetarynames.wr.usgs.gov/Page/Planets.
↑ ^10.0 ^10.1 ^10.2 Karkoschka, Erich (2001). "Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope". Icarus 151 (1): 51–68. doi:10.1006/icar.2001.6596. Bibcode: 2001Icar..151...51K.
↑ Duncan, Martin J.; Lissauer, Jack J. (1997). "Orbital Stability of the Uranian Satellite System". Icarus 125 (1): 1–12. doi:10.1006/icar.1996.5568. Bibcode: 1997Icar..125....1D.

External links

Cressida Profile by NASA's Solar System Exploration
Uranus' Known Satellites (by Scott S. Sheppard)

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Original source: https://en.wikipedia.org/wiki/Cressida (moon). Read more

[calculated-7] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 Calculated on the basis of other parameters.

[1] Benjamin Smith (1903) The Century Dictionary and Cyclopedia

[2] Kellog (1995) Boccaccio's and Chaucer's Cressida

[Jacobson_1998-3] 3.0 ^3.1 ^3.2 ^3.3 ^3.4 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. doi:10.1086/300263. Bibcode: 1998AJ....115.1195J.

[Karkoschka,_Voyager_2001-4] 4.0 ^4.1 ^4.2 ^4.3 ^4.4 ^4.5 ^4.6 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. doi:10.1006/icar.2001.6597. Bibcode: 2001Icar..151...69K.

[JPL-SSD-sat_phys-5] "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 24 October 2008. http://ssd.jpl.nasa.gov/?sat_phys_par.

[Williams_2007_nssdc-6] Williams, Dr. David R. (23 November 2007). "Uranian Satellite Fact Sheet". NASA (National Space Science Data Center). http://nssdc.gsfc.nasa.gov/planetary/factsheet/uraniansatfact.html.

[Eta-ring-8] 7.0 ^7.1 ^7.2 Chancia, Robert. A.; Hedman, Matthew M.; French, Richard G. (28 August 2017). "Weighing Uranus' moon Cressida with the η ring". The Astronomical Journal 154 (4): 153. doi:10.3847/1538-3881/aa880e. Bibcode: 2017AJ....154..153C.

[IAUC_4164-9] Smith, B. A. (January 16, 1986). "Satellites of Uranus". IAU Circular 4164. http://www.cbat.eps.harvard.edu/iauc/04100/04164.html#Item1. Retrieved 29 October 2011.

[Gazetteer-10] "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. http://planetarynames.wr.usgs.gov/Page/Planets.

[Karkoschka,_Hubble_2001-11] 10.0 ^10.1 ^10.2 Karkoschka, Erich (2001). "Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope". Icarus 151 (1): 51–68. doi:10.1006/icar.2001.6596. Bibcode: 2001Icar..151...51K.

[Duncan_Lissauer_1997-12] Duncan, Martin J.; Lissauer, Jack J. (1997). "Orbital Stability of the Uranian Satellite System". Icarus 125 (1): 1–12. doi:10.1006/icar.1996.5568. Bibcode: 1997Icar..125....1D.

v t e 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

v t e Natural satellites of the Solar System
Planetary satellites	Terrestrial Martian Jovian Saturnian Uranian Neptunian
Dwarf-planet satellites	Plutonian Haumean Makemakean Eridian OR₁₀ Quaoaran Orcean
Minor-planet moons	Main belt binaries: Antiope Frostia Berna Tokai Ostro Balam Doppler Pauling Iwamoto Wolff Bettig Christophedumas Trojans: Patroclus–Menoetius Hektor–Skamandrios Iphthime Eurydamas TNOs: Huya Typhon–Echidna Lempo–Paha–Hiisi 2002 UX₂₅ Logos–Zoe Ceto–Phorcys Borasisi–Pabu Sila–Nunam Teharonhiawako–Sawiskera Salacia–Actaea 2002 WC₁₉ Altjira Varda–Ilmarë 2003 AZ₈₄ Gǃkúnǁʼhòmdímà–Gǃòʼé ǃHú Mors–Somnus Manwë–Thorondor ǂKá̦gára–ǃHãunu 2013 FY27
Ranked by size	Planetary-mass moon Ganymede largest: 5268 km / 0.413 Earths Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Charon Umbriel Ariel Dione Tethys Dysnomia Enceladus Miranda Vanth Proteus Mimas Ilmarë Nereid Hiʻiaka Actaea Hyperion ...
Discovery timeline Inner moons Irregular moons List Planetary-mass moons Naming Subsatellite Regular moons Trojan moons

Discovery
Enhanced Voyager 2 image of Cressida
Discovered by	Stephen P. Synnott / Voyager 2
Discovery date	January 9, 1986
Designations
Designation	Uranus IX
Pronunciation	/ˈkrɛsədə/^[1]
Named after	Χρησίδα
Adjectives	Cressidian /krɛˈsɪdiən/^[2]
Orbital characteristics
Mean orbit radius	61,766.730 ± 0.046 km^[3]
Eccentricity	0.00036 ± 0.00011^[3]
Orbital period	0.463569601 ± 0.000000013 d^[3]
Inclination	0.006 ± 0.040° (to Uranus' equator)^[3]
Satellite of	Uranus
Physical characteristics
Dimensions	92 × 74 × 74 km^[4]
Mean radius	39.8 ± 2 km^[4]^[5]^[6]
Surface area	~20,000 km²^{[lower-alpha 1]}
Volume	~260,000 km³^{[lower-alpha 1]}
Mass	2.5±0.4×10¹⁷ kg^[7]
Mean density	0.86±0.16 g/cm³^[7]
surface gravity	~0.013 m/s²^{[lower-alpha 1]}
escape velocity	~0.034 km/s^{[lower-alpha 1]}
Rotation period	synchronous^[4]
Axial tilt	zero^[4]
Physics	~64 K^{[lower-alpha 1]}

Cressida (Moon)

See also

References

External links