ASTR 170B1 Lecture Notes - Lecture 9: Asteroid Family, Rockdust, Voyager 2
4 Oct 2016
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Document Summary
Made of many small solid bodies in orbit. Too close to planet, can"t form moon. Tend to spread out, but small shepherding moons can hold together. Almost all rings are close to planet. Inclined 27 degrees to orbit, so rings open and close every 15 years. From earth, see 3 bright smooth rings. Sizes: 1 cm to 10 meters (marbles to small buildings) Uranus: no internal heat source, radiates as much energy as it receives. Temperature of -210 c (60 k), is in equilibrium. Neptune: radiates 3 times more energy than it absorbs from the sun. Uranus: no internal heat, so has little convection. Neptune: lots of internal heat, drives strong convection in atmosphere. Very cold, yet complex surface (grooves faults) Maybe nearly disrupted by impact reassembles as chaotic jumble. Shepherding moons, but can"t last very long without dust being. Voyager 2 found relatively young icy surface (smooth, few craters )
