A Laplace Radius (rL)
is a limit on a radius of an orbit around a planet,
below which the orbit is not made unstable by the star.
Above this radius, the Kozai Mechanism is a factor.
rL5 = J2R2a3(1-e2)3/2M/MStar
- J2 - J2 of the planet.
- R - radius of the planet.
- a - Semi-Major Axis (a) of the planet's orbit around the star.
- e - Eccentricity (e) of the planet's orbit around the star.
- M - mass of the planet.
- MStar - the mass of the star.