|Discovered by||Mark R. Showalter|
and Jack J. Lissauer
|Discovered in||August 25, 2003|
|Semi-major axis||97,736 km|
|Orbital period||0.923 d|
|Inclination||0.1335° (to Uranus' equator)|
|Is a moon of||Uranus|
|Mean diameter||~24 km (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)|
|Atmospheric pressure||0 kPa|
Mab is a closer moon to the planet Uranus. It was found by Mark R. Showalter and Jack J. Lissauer in 2003 using the Hubble Space Telescope. It was named after Queen Mab, a fairy queen from English folklore who is noted in William Shakespeare's play Romeo and Juliet.
Because the moon is small and dark, it was not seen in the 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 look at the old photos again, and the moon was finally found in the images.
If it is as dark as Puck, then it is about 24 km in diameter. On the other hand, if it is brightly coloured like the neighbouring moon Miranda, then it would be even smaller than Cupid and comparable to the smallest farther moons.
Mab is heavily perturbed, meaning its movement is not only caused by the gravity of another large thing. The actual source for perturbation is still unclear, but is probably one or more of the nearby orbiting moons.
- Showalter, Mark R.; Lissauer, Jack J. (2005-12-22). "The Second Ring-Moon System of Uranus: Discovery and Dynamics". Science Express. 311 (5763): 973–977. doi:10.1126/science.1122882. PMID 16373533. S2CID 13240973.
- Showalter, M. R.; Lissauer, J. J. (September 25, 2003). "IAU Circular No. 8209". Retrieved 2006-08-05.
- "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. Retrieved 2006-08-05.
- 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)