Environmental Curvature Response in Planetary Dynamics: Solar System Diagnostics of the κ-Framework

The κ-framework proposes that spacetime curvature responds not only to mass but also to properties of the surrounding dynamical environment.In previous work, titled "An Environmental Curvature Response for Galaxy Rotation Curves: Empirical Tests of the κ-Framework using the SPARC Dataset," the framework was evaluated against the SPARC rotation-curve database and shown to reproduce observed galaxy rotation profiles without invoking non-baryonic dark matter.Any modification to gravitational dynamics must also remain consistent with the extremely well-constrained dynamical environment of the Solar System.Planetary motion provides a sensitive probe of weak perturbative forces through long-term orbital stability and secular perihelion motion.The present study evaluates the κ-framework in the context of planetary Solar System dynamics using high-precision N-body integrations with the REBOUND integrator.Orbital stability, secular drift, and perihelion motion are examined for representative planets spanning the inner, middle, and outer Solar System.Across all tested configurations the κ-framework produces extremely small structural perturbations to planetary orbits while introducing a measurable secular rotation of the perihelion direction.Parameter sweeps reveal three dynamical regimes: a stable regime with negligible orbital deformation, a transitional regime with increasing apsidal motion, and an unstable regime in which orbits diverge.These results indicate that the κ-framework perturbation can remain dynamically consistent with planetary Solar System behaviour within a weak forcing regime while producing measurable dynamical signatures.Pickett, J. (2026) https:/