Galatea (moon)
Voyager 2 Stephen Synnott
Galatea ( Neptune VI ) is the viertinnerste moon of the planet Neptune. He is responsible for the clumpy structures in Neptune's brightest ring.
Discovery and designation
Galatea was discovered around 28 July 1989 by Stephen P. Synnott on photographic images of the Voyager 2 spacecraft. The discovery was announced on 2 August 1989 by the International Astronomical Union ( IAU); the moon got the provisional designation S/1989 N 4
On September 16, the moon of the IAU by Galatea was named (from the Greek word for " milk white "), a daughter of Nereus and Doris, and one of about 50 Nereids ( sea nymphs ) in Greek mythology. The Greeks chose Galatea often as figurehead for their ships, as Galatea in front of the Cyclops Polyphemus fled in the form of an ever -changing wave, who wanted to marry her and her true love Akis killed out of jealousy with a boulder on which Galatea its blood in a cold river transformed.
Web properties
Orbit
Galatea orbiting Neptune on a prograde, nearly perfectly circular orbit at an average distance of 61,953 kilometers (about 2,502 Neptune radii ) from its center, ie 37,189 km above the cloud tops. The orbital eccentricity of 0.00004, the orbit is inclined 0.052 degrees from the equator of Neptune.
The orbit of the next inner moon Despina is 9430 km from Galatea's orbit removed, the next outermost moon Larissa 11.6 thousand kilometers. Nestled on the path of Galatea is a weak, very narrow yet unnamed ring in which perhaps, by the impact of micrometeorites, Galatea itself is the source.
In addition, Galatea seems the first shepherd moon of Neptune ring system, including the brightest Adams ring (1989 N1R ) to be the almost 1,000 km outside of Galatea's orbit is located. It is assumed that a 42:43 train resonance with Galatea is certainly responsible for the unique structure of the ring sheets. As for the 42 radial tangles with an amplitude of 30 km of the Adams ring this moon is also responsible, it was thus possible to determine the mass of Galatea as so far only of Neptune's moons (except Triton ) with high accuracy.
Galatea orbits Neptune in about 10 hours, 17 minutes and 23.5 seconds. Since this is faster than the rotation of Neptune, Galatea is seen from Neptune from the west, and set in the east.
The moon moves within a critical distance, near the Roche limit, in a descending orbit around the planet and is strong tidal forces exposed. The moon will eventually be torn and train as a ring or crash or burn on the surface of Neptune.
Rotation
It is believed that Galatea synchronously rotates and its axis having an inclination of 0 °.
Physical Properties
Galatea is a dark, irregularly shaped body with 204 × 184 × 144 km across and with it the fifth largest of the known moons of Neptune. The average surface temperature is set at -222 ° C ( ~ 51 K ) is estimated. Apparently, the moon was formed by no geological processes after its creation. It is likely that Galatea is one of the Rubble Piles, who have assembled loosely from fragments of the original moons that are broken apart after Neptune 's largest moon Triton was forced by Neptune on an initially very eccentric orbit.
Research
Since Galatea was only discovered during the Voyager 2 flyby, could - caused by the movement of the probe - only smeared images of Galatea are made. Since the flyby of the Neptune system ground-based observations as well as the Hubble Space Telescope has been studied intensively. 2002 - 2003 the Keck Observatory observed the system by means of adaptive optics, Galatea was able to be observed again.