Mab (moon)
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| Discovery | |||||||
|---|---|---|---|---|---|---|---|
| Discovered by | Mark R. Showalter and Jack J. Lissauer |
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| Discovered in | August 25, 2003 | ||||||
| Orbital characteristics | |||||||
| Semi-major axis | 97,736 km | ||||||
| Eccentricity | 0.0025 | ||||||
| Orbital period | 0.923 d | ||||||
| Inclination | 0.1335° (to Uranus' equator) | ||||||
| Is a satellite of | Uranus | ||||||
| Physical characteristics | |||||||
| Mean diameter | ~24 km[1] (estimate) | ||||||
| Surface area | ~1,900 km2 (estimate) | ||||||
| Volume | ~8,000 km3 (estimate) | ||||||
| Mass | ~1.0×1016 kg (estimate) | ||||||
| Mean density | ~1.3 g/cm3 (estimate) | ||||||
| Surface gravity | ~0.0044 m/s2 (estimate) | ||||||
| Escape velocity | ~0.011 km/s (estimate) | ||||||
| Rotation period | synchronous (assumed) | ||||||
| Axial tilt | zero (assumed) | ||||||
| Albedo | 0.103 | ||||||
| Surface temp. |
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| Atmospheric pressure | 0 kPa | ||||||
Mab (mab', IPA: [ˈmæb]) is an inner satellite of Uranus. It was discovered by Mark R. Showalter and Jack J. Lissauer in 2003 using the Hubble Space Telescope.[2] It was named after Queen Mab, a fairy queen from English folklore who is mentioned in William Shakespeare's play Romeo and Juliet.[3]
Because the moon is small and dark, it was not seen in the heavily scrutinized images taken by Voyager 2 during its Uranus flyby in 1986. However, it is brighter than another moon, Perdita, which was discovered from Voyager's photos in 1997. This led scientists to re-examine the old photos again, and the satellite was finally found in the images.[1]
The size of Mab is poorly constrained. If it is as dark as Puck, it is about 24 km in diameter. On the other hand, if it is brightly coloured like the neighbouring moon Miranda, it would be even smaller than Cupid and comparable to the smallest outer satellites.[1]
Mab is heavily perturbed. The actual source for perturbation is still unclear, but is presumed to be one or more of the nearby orbiting moons.[1]
Mab orbits at the same distance from Uranus as R/2003 U 1, a newly discovered dusty ring. The moon is nearly the optimal size for dust production, since larger moons can recollect the escaping dust and smaller moons have too small surface areas for supplying the ring via ring particle or meteoroid collisions. No rings associated to Perdita and Cupid have been found, probably because Belinda limits the lifetimes of dust they generate.[1]
Following its discovery, Mab was given the temporary designation S/2003 U 1.[2] The moon is also designated Uranus XXVI.[3]
[edit] References
- ^ a b c d e Showalter, Mark R., Lissauer, Jack J. (2005-12-22). "The Second Ring-Moon System of Uranus: Discovery and Dynamics". Science Express. DOI:10.1126/science.1122882.
- ^ a b Showalter, M. R.; Lissauer, J. J. (September 25, 2003). IAU Circular No. 8209. Retrieved on 2006-08-05.
- ^ a b Planet and Satellite Names and Discoverers. Gazetteer of Planetary Nomenclature. USGS Astrogeology (July 21, 2006). Retrieved on 2006-08-05.
[edit] External links
- Hubble Uncovers Smallest Moons Yet Seen Around Uranus – Hubble Space Telescope news release (2003-09-25)
- Hubble Discovers Giant Rings and New Moons Encircling Uranus – Hubble Space Telescope news release (2005-12-22)
| Moons of Uranus | |
|---|---|
| Inner | 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 |
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See also Rings of Uranus
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