2025/12/03 by Henrik Knierim, Knierim, Henrik, Konstantin Batygin +7
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2512.03961
openalex publication_date 2025/12/03 · openalex created_date 2025/12/05 · openalex updated_date 2026/08/01
The primordial structure of Jupiter remains uncertain, yet it holds vital clues on the planet's formation and early evolution. Recent work used dynamical constraints from Jupiter's inner moons to determine its primordial state, thereby providing a novel, formation-era anchor point for interior modeling. Building on this approach, we combine these dynamical constraints with thermal evolution simulations to investigate which primordial structures are consistent with present-day Jupiter. We present 4,250 evolutionary models of the planetary structure, including compositional mixing and helium phase separation, spanning a broad range of initial entropies and composition profiles. We find that Jupiter's present-day structure is best explained by a warm (4.98-2.57+3.00 \mathrmkB mu-1), metal-rich dilute core inherited from formation. To simultaneously satisfy constraints on Jupiter's primordial spin, however, its envelope must have been significantly warmer (9.32-0.58+0.48 \mathrmkB mu-1) at the time of disk dispersal. We determine Jupiter's primordial radius to be 1.89-0.49+0.40 RJ. These results provide new constraints on Jupiter's formation, suggesting that most heavy elements were accreted early during runaway gas accretion, and placing bounds on the energy dissipated during the accretion shock.