Cupid (moon)

Mark R. Showalter, Jack J. Lissauer

Cupid (also Uranus XXVII) is the ninth and one of the smallest of the 27 known moons of the planet Uranus.

Discovery and designation

Cupid was discovered on 25 August 2003 by the astronomer Mark R. Showalter and Jack Lissauer Jonathan together with Mab with the Hubble Space Telescope. He was thus the second moon in the solar system, the discovery was made with this telescope. The discovery was announced on 25 September 2003 by the International Astronomical Union ( IAU); the moon first received the provisional designation S/2003 U 2

Cupid is named after Cupid, a character from William Shakespeare's little-known tragedy of Timon of Athens. Cupid or Cupidus is also another name for the god of love Cupid in Roman mythology ( corresponding to the Greek Eros ).

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.

Web properties

Orbit

Cupid orbiting Uranus on a prograde, nearly perfectly circular orbit at an average distance of about 74,392 kilometers (about 2,911 Uranus radii ) from its center, ie 48,833 km above the cloud tops. The orbital eccentricity is 0.0013, the orbit is inclined 0.099 degrees from the equator of Uranus.

Cupid is the siebtinnerste and probably the smallest of the Portia Group, which also includes Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda and Perdita belong. These moons have similar orbits and similar spectral properties.

The orbit of the next inner moon Rosalind is on average 4465 kilometers away from Cupids orbit, that of the next outer moon Belinda only 864 km. Amazingly, the train of Cupid does not seem to be disturbed, in contrast to the other moons Perdita and Mab.

Cupid is in the midst of two Uranus rings, the inner current ν ( Ny ) dust ring whose outer edge is removed on average about 4492 km from the Cupid - orbit, and the inner edge of the outer μ ( My) dust ring in 11.6 thousand kilometers away.

Cupid Uranus rotates in 14 hours, 49 minutes and 55.20 seconds. Since this is faster than the rotation of Uranus, is Cupid seen from Uranus from the west, and set in the east.

Rotation

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

Physical Properties

Cupid has an average diameter of an estimated 12-18 km. It is assumed that Cupid has no ball round shape.

Its mean density is significantly lower than the density of the Earth at 1.3 g/cm3 and points out that the moon is composed mainly of water ice. Cupid has a very low albedo of 0.07, i.e., 7 % of the incident solar light is reflected from the surface. It is thus a very dark celestial bodies. On its surface, the gravitational acceleration is 0.0031 m/s2, this represents only about 0.03% of the earthly. The average surface temperature of Cupid is estimated to be between -184 ° C and -209 ° C ( 64-89 K).

Research

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

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