Formation of comets, planets, moons in our solar system

Formation scenarios of the solar nebula invoke two main reservoirs of water ice
that may have taken part concurrently into the production of solids. In the 
first reservoir, which is located within the heliocentric distance of 30 AU, 
water ice infalling from the Interstellar Medium (ISM) initially vaporized 
into the hot inner part of the disk and condensed in its crystalline form 
during the cooling of the solar nebula. The second reservoir, located at 
larger heliocentric distances, is composed of water ice originating from ISM 
that did not suffer from vaporization when entering into the disk. In this 
reservoir, water ice remained mainly in its amorphous form. From these 
considerations, we discuss here the trapping conditions of volatiles in 
planetesimals produced within the outer solar nebula and their implications 
for the origin and composition of gas giant planets, 
their surrounding satellite systems and comets.