Nucleation and condensation in the primitive solar nebula
1982; Elsevier BV; Volume: 52; Issue: 1 Linguagem: Inglês
10.1016/0019-1035(82)90165-8
ISSN1090-2643
AutoresA. G. W. Cameron, Bruce Fegley,
Tópico(s)Astro and Planetary Science
ResumoUsing the accretion disk physics of Lynden-Bell and Pringle, we constructed a section of a model of the primitive solar nebula, subject to the assumption that the optically thick part of the disk is convective and isentropic and that there is a steady mass flow toward the axis of the disk at the rate of 10−5 solar masses per year. The properties of the model support these assumptions. We studied that portion of the disk which includes the interface between the region where high-temperature solid condensates can exist and where they will be totally evaporated. The total evaporation front separating these two regions rises vertically off the midplane and then curves overhead inward for a long distance before emerging through the photosphere. We applied Salpeter's modification of classical condensation theory to study the nucleation and condensation of materials in gas that moves through the total evaporation front in the direction of lower temperatures. We conclude that a very substantial supercooling of the vapors is required before nucleation can take place, but the great uncertainties in the surface energies of the condensation products render the point of nucleation highly uncertain. It is probable that several materials have become unstable against condensation by the time that nucleation can take place, so that the formation and growth of condensate nuclei is likely to be a very complex process.
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