JUPITER MODELS WITH IMPROVED AB INITIO HYDROGEN EQUATION OF STATE (H-REOS.2)

Abstract

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