High Mass Nebula

High Mass Nebula - How do these theories fit the current...

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High Mass Nebula A "High-Mass" Nebula is, considered to be one where the mass is greater than about 2M S . Theories considering the solar system were formed in such a region again start with the cloud contracting to the spin plane. The large angular momentum in this massive disc leads to turbulence and increased interaction of the constituents. It is possible also that solar tidal forcing plays a part, but the end result is that the planetary bodies start to separate out: The cores form from the nebula with roughly primordial compositions, but then gas is lost from the disc due to turbulence and the evolving Sun's action. Angular momentum is transferred away from the Sun by the turbulence and viscosity of the medium. As the Sun warms up it clears the system of its un-bound volatiles, starting with the inner solar system first. Fitting the evidence to the theory
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Unformatted text preview: How do these theories fit the current hese theories fit the current morphology of the system? We know that the density of the planetary bodies tends to be higher in the inner part of the system where we expect the volatiles to have been depleted. (The terrestrial planets have a higher proportion of silicates - this gives way to water ice at larger distances from the sun and then to methane and other more volatile ices.) The nebula theories, both high and low-mass, have support in the Allende meteorite discussed above, but this does not distinguish between them. We can look more generally at meteoritic composition - a topic we shall return to nearer the end of the course, and see if the range of compositions and morphologies favours one theory over another. We can also see what material from elsewhere in the solar system might tell us....
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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