Comparison of 3, 4, 5, and 6 Layer Models of Jupiters Interior

Since its arrival at Jupiter in 2016, the Juno spacecraft has measured the planets gravity field and determined the even and odd harmonics J2 J10 with unprecedented precision. Matching these measurements with realistic interior and wind models has been a challenge because the magnitudes of J4 and J6 were unexpectedly small compared to the preliminary model described in Astrophysical Journal 820 (2016) 80. We show that this challenge can be overcome by assuming Jupiter has a dilute core. Early versions of such models have been described in Geophysical Research Letters 44 (2017) 4649. Here we employ a 5-layer interior structure, that matches the Juno gravity measurements, as a reference model that we perturb. This model includes a helium rain region, a dilute core, as well as wind contributions. As a first perturbation, we add a compact core as a sixth layer, which will diminish the dilute-core effect. We determine how massive such a compact core can be for the model to match J4 and J6. Our reference model includes two stably stratified layers, in which the helium concentrations or the amount of heavy elements vary. We remove either layer to determine which type of 4-layer model is compatible with the Juno measurements. Finally, we construct a traditional 3-layer model with a compact core and two envelope layers of differing compositions, and analyze whether the Juno measurements can still be matched under such simplified assumptions.