AST101H1 Lecture Notes - Radionuclide, Protoplanet
15 Mar 2014
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AST101H1 Full Course Notes
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Only heavy materials (metals and rocks) can condense within the frost line. Also light materials (h, he, ices) outside the frost line. Theory of solar nebula states that our solar system was created by the collapse of a dense cloud of gas. There is also a rock line, past which even rocks will vaporize (this is very close to the sun) Dust grains stick to form pebbles and rocks. When boulders form mountains (1km) gravity accelerates their growth. There is more stuff around: ice as well as rock. Once planets reach about 10 earth masses, their gravity is strong enough to pull gas out of the nebula. This leads to gas giants (jupiter and saturn) or ice giants (uranus and neptune) if there"s note enough gas. We think that the comets are the reason that earth and mars and venus got water. If the sun was cooler and dimmer, the frost line would be closer in.
