An Etymological Dictionary of Astronomy and Astrophysics

In the → three-body problem, the → perturbation of the orbit of a → secondary body by the garvity of a third body located at a distance much larger than the separation between the → primary body and the secondary. The secondary’s orbit oscillates about a constant value involving a periodic exchange between the extreme values of its → inclination and orbital → eccentricity. The Kozai-Lidov mechanism results from the conservation of the quantity (1 - e²)^1/2.cos i for each component, where e is eccentricity and i is inclination. The total → angular momentum of the system remains constant while the angular momentum is exchanged betwwen the components. It has been suggested that the Kozai mechanism is responsible for the high eccentricities observed in the orbits of → extrasolar planets. If the parent star has a massive yet unseen substellar companion, orbiting at a great distance, and in an orbit highly inclined to the plane of the planets’ orbits, the mechanism should induce high eccentricities into the orbits of the planets. Similarly, this mechanism may be responsible for the high eccentricities observed in the orbits of many → Kuiper Belt Objects such as 2003 UB313.

See also: Named for the japanese Yoshihide Kozai (1962, Astronomical J. 67, 591), and the Russian Michael Lidov (1962, Planetary & Space Science 9, 719).