Estimation of Jupiter’s Dynamical Parameters Based on Juno Two-way Doppler Tracking Data

Abstract With the continued acquisition of high-precision tracking data by the Juno spacecraft, significant progress has been made in accurately determining Jupiter’s dynamical parameters. In this study, we utilize the orbit determination and gravity field recovery software SPOT, developed by Wuhan University, to process all available two-way Doppler tracking data of Juno’s perijove passes between 2016 and 2024. Incorporating 19 additional perijoves (PJ39–PJ68) beyond the 26 arcs used in the previous study, a joint estimation of Jupiter’s 40 degree zonal gravity harmonics, four tesseral degree-2 terms, spin-axis orientation parameters, and tidal Love number is determined. The results indicate that, compared with previously published Juno-based gravity field solutions, the accuracy of coefficients J 2 –J 5 has improved by more than a factor of 2, while the J 13 –J 36 terms exhibit an average improvement of about 30%. A stochastic force was introduced to absorb unmodeled small perturbations near perijoves, but its rapidly varying orientation does not point to an identifiable physical origin. The uncertainty of Jupiter’s spin-axis rotation parameter is improved to about 1 × 10 –7 rad, indicating no significant deviation between the principal axis of inertia and the rotation axis. The estimated accuracy of the static tidal Love numbers is improved by roughly a factor of 2 compared with earlier Juno-based tidal analyses. Due to limitations in orbital geometry, the satellite-dependent tidal Love numbers cannot be determined with sufficient accuracy to reveal potential dynamical tidal effects. This work provides improved dynamical parameters for constraining Jupiter’s interior structure.