Self-consistent Evolution Models Show Weak Double-diffusive Mixing in Jupiter and Saturn
- 1California Institute of Technology
- 2University of California
Abstract
Double-diffusive convection in the “fuzzy” cores of giant planets has been widely discussed as a mechanism for redistributing heavy elements, but its efficiency in evolutionary models remains uncertain. Here we implement a prescription for transport across a double-diffusive staircase in the planetary evolution code APPLE and apply it to postformation interior models of Jupiter and Saturn that contain steep compositional gradients. We find that after evolving the models for 4.56 Gyr, the transport associated with double-diffusive convection alone cannot transform steep composition gradients and compact cores into extended, partially mixed fuzzy cores. Our results show that in both Jupiter and Saturn, double-diffusive convection redistributes ≈0.1 M ⊕ of heavy elements over the age of the solar system in our fiducial models, and at most ≈2 M ⊕ even when the effective diffusivities are enhanced by 3 orders of magnitude. We show that this inefficiency arises because the buoyancy work available to drive compositional transport is constrained by the small thermal energy budget of the deep interior, in contrast to idealized Boussinesq simulations that operate in regimes more favorable to layer merging and efficient mixing. Since the present-day interiors of Jupiter and Saturn exhibit substantially more extended heavy-element distributions, those structures must have established during formation through additional transport processes not captured by the formation models considered here.
Versions
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BibTeX
@article{fuentes2026selfconsistent,
title = {{Self-consistent Evolution Models Show Weak Double-diffusive Mixing in Jupiter and Saturn}},
author = {J. R. Fuentes and Ankan Sur and David J. Stevenson and Peter Bodenheimer},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aeacc1},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeacc1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Self-consistent Evolution Models Show Weak Double-diffusive Mixing in Jupiter and Saturn
AU - J. R. Fuentes
AU - Ankan Sur
AU - David J. Stevenson
AU - Peter Bodenheimer
PY - 2026
DA - 2026/10/16
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aeacc1
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aeacc1
AB - Double-diffusive convection in the “fuzzy” cores of giant planets has been widely discussed as a mechanism for redistributing heavy elements, but its efficiency in evolutionary models remains uncertain. Here we implement a prescription for transport across a double-diffusive staircase in the planetary evolution code APPLE and apply it to postformation interior models of Jupiter and Saturn that contain steep compositional gradients. We find that after evolving the models for 4.56 Gyr, the transport associated with double-diffusive convection alone cannot transform steep composition gradients and compact cores into extended, partially mixed fuzzy cores. Our results show that in both Jupiter and Saturn, double-diffusive convection redistributes ≈0.1 M ⊕ of heavy elements over the age of the solar system in our fiducial models, and at most ≈2 M ⊕ even when the effective diffusivities are enhanced by 3 orders of magnitude. We show that this inefficiency arises because the buoyancy work available to drive compositional transport is constrained by the small thermal energy budget of the deep interior, in contrast to idealized Boussinesq simulations that operate in regimes more favorable to layer merging and efficient mixing. Since the present-day interiors of Jupiter and Saturn exhibit substantially more extended heavy-element distributions, those structures must have established during formation through additional transport processes not captured by the formation models considered here.
SN - 0004-637X
SN - 1538-4357
ER -