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Phoebe, at 213 ± 1.4 km in diameter, is by far the largest of Saturn's irregular satellites. [30] It has a retrograde orbit and rotates on its axis every 9.3 hours. [87] Phoebe was the first moon of Saturn to be studied in detail by Cassini, in June 2004; during this encounter Cassini was able to map nearly 90% of the moon's surface.
Phoebe (/ ˈ f iː b i / FEE-bee) is the most massive irregular satellite of Saturn with a mean diameter of 213 km (132 mi). It was discovered by William Henry Pickering on 18 March 1899 [9] from photographic plates that had been taken by DeLisle Stewart starting on 16 August 1898 at the Boyden Station of the Carmen Alto Observatory near Arequipa, Peru.
Including these large moons, 24 of Saturn's moons are regular, and traditionally named after Titans or other figures associated with the mythological Saturn. The remaining 122 are irregular, and classified by their orbital characteristics into Inuit , Norse , and Gallic groups, and their names are chosen from the corresponding mythologies the ...
Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn and the sixth known planetary satellite (after Earth's moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii or 1,200,000 km above Saturn's apparent surface.
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.
The largest of these may have a hydrostatic-equilibrium shape, but most are irregular. Most of the trans-Neptunian objects (TNOs) listed with a radius smaller than 200 km have " assumed sizes based on a generic albedo of 0.09" since they are too far away to directly measure their sizes with existing instruments.
Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant , with an average radius of about nine times that of Earth . [ 27 ] [ 28 ] It has an eighth the average density of Earth, but is over 95 times more massive.
Heaviest Indian communications satellite [19] GEO: In service 2018– Cassini-Huygens: 5,655 kg (12,467 lb) Saturn orbiter and Titan probe [20] Saturn: Deorbited 2017: 1997–2017 Venera 15 & 16: 5,300 kg (11,684 lb) Venus orbiter: Venus: Retired: 1983–1985 Venera 10: 5,033 kg (11,096 lb) Venus orbiter & lander: Venus: Last contact 1976: 1975 ...