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Herschel underestimated its diameter at 260 km (160 mi) in 1802; in 1811, German astronomer Johann Hieronymus Schröter overestimated it as 2,613 km (1,624 mi). [25] In the 1970s, infrared photometry enabled more accurate measurements of its albedo, and Ceres's diameter was determined to within ten percent of its true value of 939 km (583 mi).
It has been calculated that Ceres averages one such cryovolcano every 50 million years. [45] Yamor Mons (previously named Ysolo Mons), near the north pole, has a diameter of 16 km [48] and is the only other Cererian mountain with the shape of Ahuna Mons, though old and battered, the cold temperatures at the pole have preserved its shape. [45]
This list contains a selection of objects 50 and 99 km in radius (100 km to 199 km in average diameter). The listed objects currently include most objects in the asteroid belt and moons of the giant planets in this size range, but many newly discovered objects in the outer Solar System are missing, such as those included in the following ...
Diameter (km) Discovered Spacecraft Year(s) Closest approach (km) Closest approach (asteroid radii) Notes Landmark(s) 1 Ceres: 939.4: January 1, 1801: Dawn: 2014–present: 375: 0.80: Dawn took its first "close up" picture of Ceres in December 2014, and entered orbit in March 2015: First likely dwarf planet visited by a spacecraft, largest ...
Ceres, at 950 km in diameter, is close to equilibrium, but some deviations from equilibrium shape remain unexplained. [14] Much larger objects, such as Earth's moon and the planet Mercury, are not near hydrostatic equilibrium today, [ 15 ] [ 16 ] [ 17 ] though the Moon is composed primarily of silicate rock and Mercury of metal (in contrast to ...
Diameter (km) Image Aymuray Tholi: Quechua harvest festival in May, meaning 'the song of the harvest' [132] 81 Bagach Tholus: Bagach(Багач), Belarusian harvest festival held on the 21st of September [133] 4.3 Cerealia Tholus: Cerealia,the major festival in Ancient Rome to celebrate the grain goddess Ceres (8 days in mid- to late-April ...
As of September 13, 2019, Brown's list identifies ten trans-Neptunian objects with diameters then thought to be greater than 900 km (the four named by the IAU plus Gonggong, Quaoar, Sedna, Orcus, (307261) 2002 MS 4, and Salacia) as "near certain" to be dwarf planets, and another 16, with diameter greater than 600 km, as "highly likely". [66]
Pluto is more than twice the diameter and a dozen times the mass of Ceres, the largest object in the asteroid belt. It is less massive than the dwarf planet Eris, a trans-Neptunian object discovered in 2005, though Pluto has a larger diameter of 2,376.6 km [5] compared to Eris's approximate diameter of 2,326 km. [126]