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The known icy moons in this range are all ellipsoidal (except Proteus), but trans-Neptunian objects up to 450–500 km radius may be quite porous. [ 10 ] For simplicity and comparative purposes, the values are manually calculated assuming that the bodies are all spheres.
433 Eros is a stony asteroid of the Amor group, and the first discovered, and second-largest near-Earth object.It has an elongated shape and a volume-equivalent diameter of approximately 16.8 kilometers (10.4 miles).
Outside the top four, the ranking of all the asteroids is uncertain, as there is a great deal of overlap among the estimates. The largest asteroids with an accurately measured mass, because they have been studied by the probe Dawn, are 1 Ceres with a mass of (939.3 ± 0.5) × 10 18 kg, and 4 Vesta at (259.076 ± 0.001) × 10 18 kg.
Makemake has one known moon, S/2015 (136472) 1, estimated to be some 160 kilometers (100 mi) in diameter. 47171 Lempo is a unique trans-Neptunian triple system: Lempo and its moon of roughly equal mass, Hiisi, form a close-proximity binary, separated by roughly 867 km. A second moon, Paha, orbits the Lempo–Hiisi binary at about 7411 km.
The moons of the trans-Neptunian objects (other than Charon) have not been included, because they appear to follow the normal situation for TNOs rather than the moons of Saturn and Uranus, and become solid at a larger size (900–1000 km diameter, rather than 400 km as for the moons of Saturn and Uranus).
486958 Arrokoth (provisional designation 2014 MU 69; formerly nicknamed Ultima Thule [a]) is a trans-Neptunian object located in the Kuiper belt.Arrokoth became the farthest and most primitive object in the Solar System visited by a spacecraft when the NASA space probe New Horizons conducted a flyby on 1 January 2019.
Binary asteroid 243 Ida with its small minor-planet moon, Dactyl, as seen by Galileo Binary near-Earth asteroid 65803 Didymos and its moon Dimorphos imaged by the Double Asteroid Redirection Test spacecraft. A binary asteroid is a system of two asteroids orbiting their common barycenter.
The method of modeling the asteroids' perturbations was improved, although the same number of asteroids were modeled. The ephemeris was more accurately oriented onto the ICRF. DE405 covered 1600 to 2200 to full precision. This ephemeris was utilized in the Astronomical Almanac from 2003 until 2014. DE406 was released with DE405 in 1998. A Long ...