A reproducible methodological specification, code architecture, and numerical convergence framework for studying highly inclined, retrograde Planet Nine configurations (m₉ = 6.2 M⊕, a₉ = 550 AU, e₉ = 0.3, i₉ = 145°). The pipeline implements an active point-mass integrator using REBOUND's adaptive ias15 solver, bypassing secular "wire" approximations to resolve mean-motion resonances and close-encounter scattering. A 20,000-year proof-of-concept run (N = 2,000 test particles) projects early-phase dynamical drift into Cartesian Poincaré coordinates and is coupled to a thermal-infrared detectability parameterization (WISE W1, 3.4 μm) anchored to Fortney et al. (2016). This is explicitly an initialization and convergence-boundary study, not a physical determination of shepherding efficiency, which requires integration timescales four to five orders of magnitude longer. All quantitative results derive from a pinned-seed REBOUND ias15 integration; boundaries and provenance are disclosed in full.
Mayone Maha Rajan (Fri,) studied this question.