Laomedeia (moon)
| Laomedeia | |
|---|---|
| Provisional or systematic name | S / 2002 N 3 |
| Central body | Neptune |
| Properties of the orbit | |
| Major semi-axis | 23,464,130 km |
| Periapsis | 14,522,070 km |
| Apoapsis | 32,406,190 km |
| eccentricity | 0.3810949 |
| Orbit inclination to the equator of the central body | 55.38 ° |
| Orbit inclination to the ecliptic | 37.69705 ° |
| Orbital time | 3161.22 d |
| Mean orbital velocity | 0.52 km / s |
| Physical Properties | |
| Albedo | ≈ 0.16 |
| Apparent brightness | 25.5 mag |
| Medium diameter | ≈ 42 km |
| Dimensions | ≈ 8.9920 · 10 16 kg |
| Medium density | ≈ 1.5 g / cm 3 |
| Acceleration of gravity on the surface | ≈ 0.010 m / s 2 |
| discovery | |
| Explorer |
Matthew J. Holman et al. |
| Date of discovery | August 13, 2002 |
Laomedeia (also Neptune XII ) is the third outermost moon on the planet Neptune . It is one of Neptune's prograde irregular moons .
Discovery and naming
Laomedeia was founded on August 14, 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 August 14 to September 4, 2002 and August 10, 2001 together with Halimede and Sao . The recordings were made by the 4-meter Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile and the 3.6-meter Canada-France-Hawaii Telescope in Hawaii . Several images were digitally combined until the moons, in contrast to the line-shaped stars, appeared point-like. The discovery was announced on January 13, 2003; the moon was initially given the provisional designation S / 2002 N 3 .
On February 3, 2007 the moon was named after Laomedeia (Greek for “ ruler of the people”), one of the 50 or so Nereids , sea nymphs from Greek mythology . They are the beautiful daughters of the wise old man Nereus , who was said to be prophecy and constant metamorphosis, and his wife, the Oceanid Doris .
Track properties
Laomedeia orbits Neptune on a prograde , very elliptical orbit between 14,522,070 and 32,406,190 km from its center (major orbit half-axis 23,464,130 km or 947.509 Neptune radii). The orbital eccentricity is 0.38109490, the web is 55.38 ° with respect to the equator of the Neptune inclined . The moon is in a so-called Kozai orbital resonance ; this means that its orbit inclination and eccentricity are coupled to each other (the orbit inclination decreases when the eccentricity increases and vice versa). It can therefore be assumed that these parameters are variable, since the eccentricity is also given as 0.3969 and 0.4237, the orbit inclination (compared to the ecliptic ) with 34.741 ° and the major orbit half-axis with 23.571 million km.
The orbit of the next inner moon Sao is on average about 1.3 million km from Laomedeia's orbit, the distance of the orbit of the next outer moon Psamathe is twenty times, on average about 25.9 million km; the Psamathe orbit is a little more than twice as far from Neptune.
Laomedeia orbits Neptune in around 3,161 days, 5 hours and 17 minutes or around 8,661 earth years, i.e. longer than the four inner planets, the dwarf planet Ceres and most of the asteroids of the main belt around the sun need.
Physical Properties
Laomedeia is estimated to be 42 km in diameter based on its assumed retroreflective power of 16%. Their density is estimated at 1.5 g / cm 3 . This means that the moon is mostly composed of water ice .
Laomedeia is believed to be a captured asteroid.
exploration
Due to the great distance to Neptune and the weak brightness of 25.5 mag, which is 1: 12200000 compared to the central planet, Laomedeia was not found during the flyby of Voyager 2 in 1989. Since its discovery in 2002, Laomedeia could only be observed through earth-based telescopes and its orbital elements and their brightness could be determined.
Web links
- IAUC 8047: Satellites of Neptune Jan 13, 2003 (discovery)
- IAUC 8802: Satellites of Neptune February 3, 2007 (numbering and naming)
- IAU: Natural Satellites Ephemeris Service IAU: Orbital parameters and ephemeris of irregular moons
- NASA: Planetary Satellite Physical Parameters NASA: Physical Parameters (English)
- NASA: Planetary Satellite Mean Orbital Parameters NASA: Orbital Parameters (English)
- NASA: Neptunian Satellite Fact Sheet NASA: List of Parameters
- Scott S. Sheppard: Neptune's Known Satellites List with parameters of the Neptune system (English)
- USGS: Planet and Satellite Names and Discoverers Names of planets and satellites
- Polish moon page: Laomedeia description and further links (English)