Rosalind (moon)

Voyager 2 Stephen P. Synnott

Rosalind (also Uranus XIII ) is the eighth and one of the smaller of the 27 known moons of the planet Uranus.

Discovery and designation

Rosalind was discovered on 13 January 1986 by the astronomer Stephen P. Synnott together with Desdemona and Belinda on photographic images of the Voyager 2 spacecraft. The discovery was announced on 16 January 1986 by the International Astronomical Union ( IAU); the moon first received the provisional designation S/1986 U 4

Rosalind is the daughter of Duke Senior from William Shakespeare's comedy As You Like It. Duke Senior is ousted by his younger brother Frederick and goes into the Ardennes forest in exile. As Orlando, who is in love with Rosalind, after winning a fight - which was engineered by his older brother Oliver - learns that Duke Frederick he is jealous, he follows a senior in the Ardennes. Rosalind is then banished from Friedrich, and flees as a man "Ganymede " disguised and accompanied by the friend of her Celia, the daughter of Frederick, also in the Ardennes. She meets Orlando, Rosalind feels as lost and love writing poems, however, are not visible to interview Orlando about his true feelings for her; she explains, to cure him of his heartache when Orlando Ganymede as courting, as it were Rosalind, which is in agreement. After Oliver, who had been sent by Frederick, had been rescued from Orlando and Oliver had fallen in love with Celia, she revealed Orlando in their wedding their true identity.

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

Rosalind orbiting Uranus on a prograde, nearly perfectly circular orbit at an average distance of about 69,927 kilometers (about 2,736 Uranus radii ) from its center, ie 44,368 km above the cloud tops. The orbital eccentricity of 0.00011, the orbit is inclined 0.27876 ° relative to the equator of Uranus.

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

The orbit of the next inner moon Portia is on average 3830 kilometers away from Rosalind's orbit, the moon of the next outer Cupid 4465 km. Rosalind is close to a 8:7 orbital resonance with - Perdita.

Rosalind is surrounded by two rings Uranus, its orbit lies almost exactly on the outer edge of the inner ν ( Ny ) dust ring, while the average distance to the inner edge of the outer μ ( My) dust ring is about 16,000 km.

Rosalind Uranus rotates in 13 hours, 24 minutes and 10.90 seconds. Since this is faster than the rotation of Uranus, is Rosalind seen from Uranus from the west, and set in the east. Rosalind needed for a full circulation apparent from the perspective of a fictional observer on Uranus Uranus almost 3.5 days and stands after two rounds ( at 6.99 Uranus days, a "Uranus - week " ) almost at the same location on the sky Uranus, about 1 ° to the west.

Rotation

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

Physical Properties

Rosalind has an average diameter of 72 km. It is assumed that Rosalind has no ball round shape; However, this could not be determined in the pictures of the Voyager 2 probe.

Their average density is much lower than the density of the Earth at 1.3 g/cm3 and points out that the moon is composed mainly of water ice. It 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 0.0131 m/s2, corresponding to about 1 ‰ of the earth. The average surface temperature of Rosalind is at -184 to -209 ° C ( 89-64 K ) is estimated.

Otherwise, not much is known about this moon since images of the probe came at a great distance and therefore have a low resolution.

Research

Since the flyby of the Voyager 2 spacecraft, the Uranus system of ground-based observations as well as the Hubble Space Telescope has been studied intensively. The orbital parameters of Rosalind could be clarified.