Cressida (moon)
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| Discovery | |
|---|---|
| Discovered by: | Stephen P. Synnott / Voyager 2 |
| Discovery date: | January 9, 1986 |
| Orbital characteristics | |
| Mean radius of orbit: | 61,766.730 ± 0.046 km[1] |
| Eccentricity: | 0.00036 ± 0.00011[1] |
| Orbital period: | 0.463569601 ± 0.000000013 d[1] |
| Inclination: | 0.006 ± 0.040° (to Uranus' equator)[1] |
| Satellite of: | Uranus |
| Physical characteristics | |
| Dimensions: | 92 × 74 × 74 km[2] |
| Mean radius: | 41 ± 2 km[2] |
| Surface area: | ~20,000 km²[3] |
| Volume: | ~260,000 km³[3] |
| Mass: | ~3.4×1017 kg[3] |
| Mean density: | ~1.3 g/cm³ (assumed) |
| Equatorial surface gravity: | ~0.013 m/s2[3] |
| Escape velocity: | ~0.034 km/s[3] |
| Rotation period: | synchronous[2] |
| Axial tilt: | zero[2] |
| Albedo: | 0.08 ± 0.01[4] |
| Temperature: | ~64 K[3] |
Cressida is a closer moon to Uranus. It was found from the images taken by Voyager 2 on 1986-01-09, and was given the designation S/1986 U 3.[5] It was named after 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.[6]
Cressida belongs to Portia Group of moons, which also includes Bianca, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda and Perdita.[4] These moons have similar orbits and photometric properties.[4] Unfortunately, other than its orbit,[1] radius of 41 km[2] and geometric albedo of 0.08[4] almost nothing is known about it.
At the Voyager 2 images Cressida appears as a stretched object, the major axis pointing towards Uranus. The ratio of axises of the Cressida's prolate spheroid is 0.8 ± 0.3.[2] Its surface is grey in color.[2]
[change] References
- ↑ 1.0 1.1 1.2 1.3 1.4 Jacobson, R.A. (1998). "The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager2 Observations". The Astronomical Journal 115: 1195-1199. DOI:10.1086/300263.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Karkoschka, Erich (2001). "Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites". Icarus 151: 69–77. DOI:10.1006/icar.2001.6597.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Calculated on the basis of other parameters
- ↑ 4.0 4.1 4.2 4.3 Karkoschka, Erich (2001). "Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope". Icarus 151: 51–68. DOI:10.1006/icar.2001.6596.
- ↑ Smith, B. A. (January 16, 1986). IAU Circular No. 4164. Retrieved on 6 August 2006.
- ↑ Planet and Satellite Names and Discoverers. Gazetteer of Planetary Nomenclature. USGS Astrogeology (July 21, 2006). Retrieved on 6 August 2006.
[change] Other websites
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| Moons | Ariel ·Belinda ·Bianca ·Caliban ·Cordelia ·Cressida ·Cupid ·Desdemona ·Ferdinand ·Francisco ·Juliet ·Mab ·Margaret ·Miranda ·Oberon ·Ophelia ·Perdita ·Portia ·Prospero ·Puck ·Rosalind ·Setebos ·Stephano ·Sycorax ·Titania ·Trinculo ·Umbriel Other: Arieal features ·Miranda features ·Oberon features ·Titania features ·Puck Craters ·Umbriel craters · Miranda's Verona Rupes ·Umbriel Crater Wunda |
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| Characteristics | Atmosphere ·Rings of Uranus | |
| Discovery | William Herschel ·William Lassell | |
| Exploration | Voyager program ·Voyager 2 | |
| Other | 15 Orionis ·Uranus-crosser asteroid ·In fiction | |
