 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
Start with material of solar composition material
|
|
|
|
|
(H, He, C, N, O, Ne, Mg,
Si, S, Fe ...)
|
|
|
| |
Material starts out hot enough that everything is a gas
|
|
|
|
|
May not be exactly true but is simplest starting point
|
|
|
| |
As gas cools, different chemicals condense
|
|
|
|
|
First high temperature chemicals, then intermediate
ones, then ices
|
|
|
| |
Solids begin to stick together or accrete
|
|
|
|
|
snowflakes snowballs (Velcro Effect)
|
|
|
| |
Once large enough gravity pulls solids together into planetesimals
|
|
|
|
|
planetesimals grow with size
|
|
|
| |
At some point wind from sun expels all the gas from the system
|
|
|
|
|
Only the solid planetesimals remain to build planets
|
|
|
|
|
Composition depends on temperature at that point (in time and
space)
|
|
|
|
Gas can only remain if trapped in the gravity of a large enough
planet
|
|