15.13-P

More Random Models of Uranus and Neptune

M. Podolak (Tel Aviv University), J. I. Podolak (Struma 5), M. S. Marley (New Mexico State Univ.)

Uncertainties in the composition and thermal structure of Uranus and Neptune make it desirable to try to calculate the limits for the density distribution inside these planets which are, as much as possible, independent of other assumptions. To this end Marley et al. (1995) computed Monte Carlo models where the density distribution was allowed to be random, subject to the constraint that the density increase monotonically towards the center. They found that a density jump was required for both planets at a radius of about 0.6 to 0.7 of the total radius. We have used a more efficient algorithm to explore the parameter space, and to find what limits can be set on the density discontinuity. For Neptune we find that the uncertainties in the measured value of tex2html_wrap_inline11 are large enough so that models with no discontinuity are possible. For Uranus a discontinuity is required, however. The limits on the size and position of this discontinuity are presented and the implications for the compostion are discussed.

Marley, M. S., Gomez, P., and Podolak, M. (1995). Monte Carlo models for Uranus and Neptune. J. Geophys. Res. 100:23,349-23,353.