TY - JOUR

T1 - Computation of Jupiter interior models from gravitational inversion theory

AU - Hubbard, W. B.

AU - Horedt, G. P.

N1 - Funding Information:
We thank D. J. Stevenson for helpful comments on this paper. This research was supported in part by NASA Grant NAGW-192 (Jupiter Data Analysis Program), and by NASA Grant NSG-7045.

PY - 1983/6

Y1 - 1983/6

N2 - A method for deriving a planetary interior model which exactly satisfies a set of N gravitational constraints is implemented. For Jupiter, recent spacecraft measurements provide the mass, radius at a standard pressure level, rotation law, multipole moments of the internal mass distribution, and constraints on the internal composition and temperature distribution. By appropriate iterations, interior models are found which exactly satisfy these constraints. The models are assumed to have constant chemical composition and constant specific entropy in the hydrogenic envelope. The derived pressure-density relation in the outer envelope depends sensitively on the observational uncertainty in the mass multipole moment J4. Models are not forced to fit the more indirectly derived constraints, which are instead used as consistency checks. For a helium mass fraction in the envelope (Y) equal to 0.20, the inferred pressure at a mass density ≈ 0.2 g/cm3 is about a factor of 2 higher than would be indicated by experimental hydrogen shock compression data in the relevant pressure range of 105 to 106 bar. The inferred pressure distribution is in much better agreement with the shock data for a nominal Y = 0.30 ± 0.05. This value of Y is interpreted in terms of an enhancement in the envelope, by a factor of order 5 over solar abundance, of species primarily consisting of CH4, NH3, and possibly H2O. The same method is applied to Saturn, but existing uncertainties in Saturn's gravitational parameters are still too large to allow useful conclusions about the composition of its envelope.

AB - A method for deriving a planetary interior model which exactly satisfies a set of N gravitational constraints is implemented. For Jupiter, recent spacecraft measurements provide the mass, radius at a standard pressure level, rotation law, multipole moments of the internal mass distribution, and constraints on the internal composition and temperature distribution. By appropriate iterations, interior models are found which exactly satisfy these constraints. The models are assumed to have constant chemical composition and constant specific entropy in the hydrogenic envelope. The derived pressure-density relation in the outer envelope depends sensitively on the observational uncertainty in the mass multipole moment J4. Models are not forced to fit the more indirectly derived constraints, which are instead used as consistency checks. For a helium mass fraction in the envelope (Y) equal to 0.20, the inferred pressure at a mass density ≈ 0.2 g/cm3 is about a factor of 2 higher than would be indicated by experimental hydrogen shock compression data in the relevant pressure range of 105 to 106 bar. The inferred pressure distribution is in much better agreement with the shock data for a nominal Y = 0.30 ± 0.05. This value of Y is interpreted in terms of an enhancement in the envelope, by a factor of order 5 over solar abundance, of species primarily consisting of CH4, NH3, and possibly H2O. The same method is applied to Saturn, but existing uncertainties in Saturn's gravitational parameters are still too large to allow useful conclusions about the composition of its envelope.

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U2 - 10.1016/0019-1035(83)90240-3

DO - 10.1016/0019-1035(83)90240-3

M3 - Article

AN - SCOPUS:0039196671

VL - 54

SP - 456

EP - 465

JO - Icarus

JF - Icarus

SN - 0019-1035

IS - 3

ER -