User:Amirber/Dwarf moons
A dwarf moon is a planetary-mass object that is a satellite but is too small to be considered a moon. More explicitly, the International Astronomical Union (IAU) will define a dwarf moon as a celestial body in direct orbit of a planetor a dwarf planet that is not massive enough for its shape to be controlled by gravitation. Thees moons are routhly 1,000 Km in diameter or larger.
For example, Jupiter has nearly 70 "moons", however only the 4 galilean moons are large enough not to be considerd "dwarf". Mars's two "moons" are both thout to be asteroids gravitationaly captured and should be both considered to be "dwarf moons".
Natural satellites of the Solar System taken from Moons[edit]
The seven largest natural satellites in the Solar System (those bigger than 2,500 km across) are Jupiter's Galilean moons (Ganymede, Callisto, Io, and Europa), Saturn's moon Titan, Earth's moon, and Neptune's captured natural satellite Triton. Triton, the smallest of these, has more mass than all smaller natural satellites together. Similarly in the next size group of nine natural satellites, between 1,000 km and 1,600 km across, Titania, Oberon, Rhea, Iapetus, Charon, Ariel, Umbriel, Dione, and Tethys, the smallest, Tethys, has more mass than all smaller natural satellites together. As well as the natural satellites of the various planets, there are also over 80 known natural satellites of the dwarf planets, asteroids and other small Solar System bodies. Some studies estimate that up to 15% of all trans-Neptunian objects could have satellites.
The following is a comparative table classifying the natural satellites in the Solar System by diameter. The column on the right includes some notable planets, dwarf planets, asteroids, and trans-Neptunian objects for comparison. The natural satellites of the planets are named after mythological figures. These are predominately Greek, except for the Uranian natural satellites, which are named after Shakespearean characters. The nineteen bodies massive enough to have achieved hydrostatic equilibrium are in bold in the table below. Minor planets and satellites suspected but not proven to have achieved a hydrostatic equilibrium are italicized in the table below.