Academic Journal
Resolving core-envelope degeneracies in giant planets and sub-Neptunes: Constraining the equivalence in the presence of dilute gradients.
| Τίτλος: | Resolving core-envelope degeneracies in giant planets and sub-Neptunes: Constraining the equivalence in the presence of dilute gradients. |
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| Συγγραφείς: | Wilkinson, C.1 (AUTHOR) christian.wilkinson@obspm.fr, Charnay, B.1 (AUTHOR), Mazevet, S.2 (AUTHOR), Perrier, B.1 (AUTHOR), Lagrange, A.-M.1 (AUTHOR), Delaye, L.1 (AUTHOR) |
| Πηγή: | Astronomy & Astrophysics / Astronomie et Astrophysique. 2026, Vol. 713, p1-18. 18p. |
| Θεματικοί όροι: | *Planetary interiors, *Concentration gradient, *Hydrostatic equilibrium, *Neptune (Planet), *Gas giants |
| Περίληψη: | Context. The widespread recognition of dilute, 'fuzzy' cores in giant planets and massive volatile mantles in sub-Neptunes has transformed planetary interior modelling into a highly degenerate, multi-dimensional problem. Aims. To map the structural degeneracies introduced by these complex interiors, 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 (Mp, Rp, Zatm), enabling consistent forwardmodel exploration of interior degeneracies across the radius valley and the warm-giant population. Methods. The framework solves the equations of hydrostatic equilibrium across phase-separated iron, rock, and water layers beneath a gaseous envelope. We employed a highly resolved adaptive grid to model arbitrary heavy-element gradients within the envelope, parameterising the dilution width to systematically evaluate the structural impact of varying core-envelope boundaries. Results. We benchmarked fuzzycore against an evolution-derived Jupiter profile, demonstrating that when envelope boundary metal-licities and integrated heavy-element budgets are matched, the macroscopic planetary radius is robust to the exact functional topology of the gradient to within 2.3%. This empirical robustness allowed us to use smooth parameterisations to densely map interior degeneracies. Applying this to the sub-Neptune regime, we generated a water-world degeneracy atlas, quantifying how the required envelope metallicity and dilution width trade off against assumed water-mass fractions to reproduce a fixed planetary radius. Conclusions. By decoupling structural profiling from time-dependent energy transport and convective mixing, fuzzycore enables the systematic mapping of static degeneracies across the sub-Neptune and warm-giant populations at resolutions that complement, rather than replace, fully evolutionary Henyey treatments. It serves as a forward-model backend for linking atmospheric metallicity priors from JWST and Ariel to deep interior architectures. [ABSTRACT FROM AUTHOR] |
| Βάση Δεδομένων: | Academic Search Index |
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