Mab (moon)

Mark R. Showalter, Jack J. Lissauer

Mab (also Uranus XXVI) is the thirteenth and one of the smaller of the 27 known moons of the planet Uranus.

  • 3.1 size
  • 3.2 Surface
  • 3.3 Internal structure

Discovery and designation

Mab was discovered on 25 August 2003 by the astronomer Mark R. Showalter and Jack J. Lissauer using the Hubble Space Telescope. He was the first satellite in the solar system, the discovery was made with this telescope. The moon was sighted on old photos of the Voyager 2 probe. The discovery was announced on 25 September 2003 by the International Astronomical Union ( IAU); the moon first received the provisional designation S/2003 U 1

The moon has the official name for a Mab mentioned in Shakespeare's Romeo and Juliet Queen Mab, the midwife of Feenköniginnen obtained. The figure comes from English folklore from the 17th century. It was probably by Medb, the legendary Queen of Connacht inspired.

All the moons of Uranus are named after characters from Shakespeare or Alexander Pope. The first four moons discovered Uranus ( Oberon, Titania, Ariel, Umbriel ) were proposed by John Herschel, the son of Uranus discoverer William Herschel, named. Later, the tradition of naming was retained. The provisional designation S/2003 U 1 is the scheme of the IAU.

Web properties

Orbit

Mab orbiting Uranus on a prograde, nearly perfectly circular orbit at an average distance of about 97,736 kilometers (about 3,824 Uranus radii ) from the center, or about 72,200 km above the cloud tops. The orbital eccentricity is 0.0025, the orbit is inclined 0.1335 ° relative to the equator of Uranus.

The orbit of the next inner moon Puck is on average 11.7 thousand kilometers away from Mabs orbit, that of the next outer moon Miranda 31,650 km. Mab is the outermost of the inner group of 13 regular small moons of Uranus, which he together forms a separate subgroup with Puck.

Mab is in the midst of μ ( My) dust ring of the inner and outer edge it is about 11,700 km or 5200 km away. The brightest and densest part of the outermost ring of Uranus falls almost exactly with the orbit of the moon and is presumably the source of the ring particles. Mab Uranus rotates in 22 hours 8 minutes.

Rotation

It is believed that Mab synchronously rotates and its axis having an inclination of 0 °.

Physical Properties

Size

The size of the Moon is not sufficiently known, it is about 16 km. There is information 10-24 km, which is probably due to the uncertainty of the albedo, which is given as 0.07 to 0.103 (ie, 7 or 10% of the incident sunlight is reflected from the surface, and he is thus a relatively dark celestial bodies ). If Mab be brighter than expected, the lower value of 10 km is more likely, which would make it the smallest known Uranus moon.

Surface

The cratered surface of the moon shows up strong. The source of the strong bombardment is not known, but it is believed that one or two adjacent satellites are responsible. Mab seems to be the source of the μ ( My) dust ring to be what he would have the optimum size. More massive satellites would pick up the dust again, while less massive would be too small to feed such a ring by collisions or micro- meteorite impacts. No dust rings were found to Perdita and Cupid, which is possibly due to the moon Belinda, which limits the lifetime of the dust produced by these moons.

The average surface temperature of Mab is on between -184 ° C and -209 ° C ( 89-64 K ) is estimated.

Internal construction

Its mean density is significantly lower than the density of the Earth at 1.3 g/cm3 and points out that the moon is made ​​up predominantly of water ice. On its surface, the gravitational acceleration is 0.0032 m/s2, this represents only about 0.03% of the earthly.

Research

Since the flyby of the Voyager 2 spacecraft in which Mab by the small size and brightness could not be found, the Uranus system of ground-based observations as well as the Hubble Space Telescope has been studied intensively. The orbital parameters of Mab could be clarified.

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