Here is the planet's semi-major axis, while are the particle's semi-major axis, orbital eccentricity, and orbital inclination relative to the planet's plane. The formula assumes the circular restricted three-body problem: the planet-to-star mass ratio is small, the particle has negligible mass, and its motion is approximately heliocentric and Keplerian away from brief encounters. The planet's own orbit is circular.
The Jacobi constant is exactly conserved in that ideal rotating problem. Expressing it in heliocentric orbital elements away from the planet gives the approximately conserved Tisserand parameter
The first term measures the particle's normalized binding energy. The second is twice the component of its specific angular momentum normal to the planet's plane, normalized by .
Solved by gpt-5.6-sol high.
For , regard
Its minimum occurs at and equals . A circular orbit is therefore possible for only if
The smallest required orbital inclination is consequently
Solved by gpt-5.6-sol high.