Laomedeia (moon)

Matthew J. Holman et al.

Laomedeia ( Neptune XII ) is a moon of the planet Neptune. He is one of prograde irregular moons of Neptune.

Discovery and designation

Laomedeia was on 14 August 2002 by a team consisting of Matthew J. Holman, John J. Kavelaars, Tommy Grav, Brett J. Gladman, Wesley C. Fraser, Dan Milisavljevic, Philip D. Nicholson, Joseph A. Burns, Valerio Carruba, Jean -Marc Petit, Philippe Rousselot, Oliver Mousis, Brian G. Marsden and Robert A. Jacobson on recordings from 14 August to 4 September 2002, and on 10 August 2001 discovered along with Halimede and Sao. The recordings were made by the 4.0 -meter Blanco telescope at the Cerro Tololo Inter- American Observatory in Chile, and the 3.6 -meter Canada -France - Hawaii Telescope in Hawaii. Several recordings were digitally combined until the moons as opposed to the line-shaped stars appeared point-like. The discovery was announced on 13 January 2003; the moon first received the provisional designation S/2002 N 3

On 3 February 2007, the moon was named after Laomedeia (Greek for "people's ruler " ), one of about 50 sea nymphs Nereids in Greek mythology. They are the beautiful daughters of the wise old man Nereus, the prophecy and constant transformation have been rumored, and his wife, Doris of Oceanid.

Web properties

Laomedeia orbits Neptune on a prograde, very elliptical orbit 14522070-32406190 km Distance to the center ( large semi-major axis 23,464,130 km or 947.509 Neptune radii ). The orbital eccentricity is 0.38109490, the orbit is inclined 55.38 ° relative to the equator of Neptune. The moon is in a so-called Kozai - orbital resonance, which means that its orbital inclination and eccentricity are coupled to each other ( the orbital inclination decreases when increasing the eccentricity, and vice versa). It can therefore be assumed that these parameters are variable, since the eccentricity is specified with 0.3969 and 0.4237, the orbital inclination ( with respect to the ecliptic ) with 34.741 ° and the Great semi-major axis with 23.571 million km.

The orbit of the next inner moon Sao is on average about 1.3 million km away from Laomedeias orbit, the distance of the path of the next outer moon Psamathe is twenty times, on average, about 25.9 million km; the web from Psamathe is slightly more than twice as far from Neptun.

Laomedeia orbits Neptune in about 3,161 days 5 hours and 17 minutes or about 8.661 Earth years, ie longer than the four inner planets, the dwarf planet Ceres and the majority of the asteroids of the main belt need around the sun.

Physical Properties

Laomedeia has a diameter of 42 km estimated, based on the assumed for them albedo of 16%. The surface is thus relatively dark. Their density is estimated to be 1.5 g/cm3. So the moon is likely to be composed predominantly of water ice.

It is believed that the moon is a captured asteroid.

Research

Because of the great distance to Neptune and weak brightness of 25.5 like the 1:12200000 is opposite to the central planet, Laomedeia was not found during the flyby of Voyager 2 in 1989. Since the discovery in 2002 Laomedeia could only be observed by ground-based telescopes, while their orbital elements and their brightness can be determined.

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