Jupiter models with improved ab initio hydrogen EOS (H-REOS.2)

The amount and distribution of heavy elements in Jupiter gives indications on the process of its formation and evolution. Core mass and metallicity predictions however depend on the equations of state used, and on model assumptions. We present an improved ab initio hydrogen equation of state, H-REOS.2 and compute the internal structure and thermal evolution of Jupiter within the standard three-layer approach. The advance over our previous Jupiter models with H-REOS.1 by Nettelmann et al.(2008) is that the new models are also consistent with the observed 2 or more times solar heavy element abundances in Jupiters atmosphere. Such models have a rock core mass Mcore=0-8 ME, total mass of heavy elements MZ=28-32 ME, a deep internal layer boundary at 4 or more Mbar, and a cooling time of 4.4-5.0 Gyrs when assuming homogeneous evolution. We also calculate two-layer models in the manner of Militzer et al.(2008) and find a comparable large core of 16-21 ME, out of which ~11 ME is helium, but a significantly higher envelope metallicity of 4.5 times solar. According to our preferred three-layer models, neither the characteristic frequency (nu0 ~156 microHz) nor the normalized moment of inertia (~0.276) are sensitive to the core mass but accurate measurements could well help to rule out some classes of models.

Thermophysical properties of warm dense hydrogen

We study the thermophysical properties of warm dense hydrogen using quantum molecular dynamics simulations. New results are presented for the pair distribution functions, the equation of state, the Hugoniot curve, and the reflectivity. We compare with available experimental data and predictions of the chemical picture. Especially, we discuss the nonmetal-to-metal transition which occurs at about 40 GPa in the dense fluid.

Equation of state for dense hydrogen and plasma phase transition

We calculate the equation of state of dense hydrogen within the chemical picture. Fluid variational theory is generalized for a multi-component system of molecules, atoms, electrons, and protons. Chemical equilibrium is supposed for the reactions dissociation and ionization. We identify the region of thermodynamic instability which is related to the plasma phase transition. The reflectivity is calculated along the Hugoniot curve and compared with experimental results. The equation-of-state data is used to calculate the pressure and temperature profiles for the interior of Jupiter.