A Two‐dimensional Model for the Primordial Nebula Constrained by D/H Measurements in the Solar System: Implications for the Formation of Giant Planets

Abstract

Using the density and temperature profiles resulting from a two-dimensional turbulent model of the solar nebula as well as an appropriate law for the time variation of the disk accretion rate, we integrate the equation of diffusion that rules the evolution of the D/H ratio in H2O and HCN throughout the nebula. By fitting D/H measured in LL3 meteorites and comets or inferred in proto-Uranian and proto-Neptunian ices, we constrain the parameters of the model, namely, the initial accretion rate M(0), the initial radius of the turbulent disk RD, and the α-coefficient of turbulent viscosity, and we find 2×10-6 <10-5 Msolar yr-1, 12.8