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Unformatted text preview: Formation of the Solar System Any model for the formation of the SS has to explain many non-trivial general patterns: i. oldest age of any SS body is <4.6x10 9 y; many meteorites are this age ii. orbits of planets, and Suns equator, lie in a single plane. Orbits are nearly circular. iii. planets all revolve in the same direction that the Sun rotates iv. Sun has 99.9% of mass but planets (mostly Jupiter) have 98% of angular momentum v. inner planets are denser, made of rare elements like silicates, metals; outer planets composition more like solar vi. asteroid composition transitional with inner more rocky/silicate and outer more ices vii. oldest meteorites have grains that cooled at T ~ few hundred K viii. comet composition dominated by ices ix. volatiles present in inner SS x. giant planets all have regular satellites and ring systems orbiting in planets equatorial plane The Solar Nebula The Suns cocoon nebula extended at least 40 AU, and probably several hundred AU from the forming Sun The protoplanetary disk condensed directly out of this nebula: it was not (for example) ejected from the Sun. If planets form from such disks, this explains why orbits are all in the plane of the Sun, and orbit in the same direction as the Suns rotation. Mostly composed of hydrogen and helium Also many volatile elements such as inert gases, water vapour These volatiles have a high vapour pressure: in a vacuum they will sublime from a solid state Heated by the Sun, but also accretion of matter onto the disk, friction, and magnetic flares....
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This note was uploaded on 04/15/2009 for the course PHYS 275 taught by Professor Harris during the Winter '09 term at Waterloo.
- Winter '09