Ten of 32 tested orientations of HD 153557 b and c median elements have no detected encounter for 100 years in Newtonian models with a 0.79 solar mass star

We test whether unknown orbital orientations change the rapid encounter result for the reported median elements of HD 153557 b and c. We use the corrected public CDS table and fix the stellar mass at 0.79 solar mass. We test 32 fixed orientations with sky inclinations from 30 to 150 degrees. Model masses equal the tabulated minimum masses divided by the sine of each inclination. Each orientation has an astrocentric model and a Jacobi model. These mappings give different physical initial states. Each mapping gives 20 encounters and 12 tests that reach 100 years. Ten orientations reach 100 years in both mappings. Two extra coplanar controls reach the encounter threshold within 186 days. The threshold is one initial mutual Hill radius, checked along each integration-step chord. The common case with the largest smaller separation margin reaches an encounter at 244.28 and 244.49 years in its two base extensions. All six planned extensions reach the threshold between 242.9 and 249.5 years. These include tighter numerical settings and a fixed test with outer companion d. Thus the 100-year result does not extend to 1000 years. The package includes the full design, source data, code, initial and final states, annual traces, figures, and numerical checks. The counts describe a numerical design, not probabilities for the real system. The tests use Newtonian point masses. They do not fit measured velocities, prove long-term stability, or establish a new planet.

HD 153557 · orbital dynamics · mutual inclination · radial velocity planets · finite numerical tests · reproducible data