An edge-on point-mass Hill model gives a 3.79% radius correction for TOI-6255 b at saved catalog inputs

We tested the leading-order shape formula for the five lava planets in JWST program 8864. We used a frozen NASA Planetary Systems extract from 24 October 2026. Four targets have measured masses in that extract. For each, we solved the closed point-mass Hill surface that has the catalog transit area. The model assumes a circular synchronous orbit, zero obliquity, and an edge-on view. For TOI-6255 b, the nonlinear volume-radius increase is 3.79%, compared with 3.09% at leading order. Its quadrature-area increase is 10.63%, compared with 7.94%. For TOI-2431 b, the corresponding nonlinear increases are 2.68% and 7.34%. Corrections are smaller for TOI-1807 b and TOI-431 b. TOI-2260 b has no measured mass in the source extract, so we give an assumed mass grid. Eight marginal error corners per measured-mass target test input sensitivity. They are not confidence intervals. Angular convergence, an independent surface mesh, weak and critical limits, and full circular Roche controls test the numerical method. The finite-mass controls change the central radius and area corrections by less than 0.0003 percentage points. A second-order series gives an additional algebra check. These results are a numerical reference set. They do not measure planetary shapes or include rigidity and deformation of planetary self-gravity. The package preserves source code, frozen data, provenance, figures, numerical checks, and reproduction instructions.

tidal deformation · Hill potential · Roche potential · lava planets · transit radius · projected area · JWST program 8864 · TOI-6255 b · TOI-2431 b · reproducible calculation