Resolving core-envelope degeneracies in giant planets and sub-Neptunes: constraining the equivalence in the presence of dilute gradients
The widespread recognition of dilute, "fuzzy" cores in giant planets and massive volatile mantles in sub-Neptunes has made interior modelling a highly degenerate, multi-dimensional problem. To map these degeneracies, we present fuzzycore, an open-source static structural integrator with a unified layered architecture spanning rock-water-envelope sub-Neptunes through volatile-rich gas giants. The framework supports dense parameter sweeps over compositional gradients at fixed observed $(M_p, R_p,…