Quasi-satellite Orbits Research Articles

Stability limits for the quasi-satellite orbit

An asteroid moving around the Sun having approximately the same mean motion and mean longitude as a planet, but a different eccentricity, circles the planet like a retrograde satellite even when the distance is large enough so that it is not a bound satellite. If the orbits are coplanar, then the motion is stable in the secular approximation. When the orbits are inclined enough, an asteroid can be trapped into such a quasi-satellite (QS) motion for a finite period of time. The conditions under which this can occur are discussed, improved criteria for the recognition of this type of motion are developed, and numerical examples from real QS objects are provided.

The Stability of Quasi Satellites in the Outer Solar System

Quasi satellites are bodies in a particular configuration of a 1 : 1 mean motion resonance, one in which they librate about the longitude of their associated planet. We investigate numerically the stability of such orbits around the giant planets of our solar system. We find that test particles can remain on quasi-satellite orbits around Uranus and Neptune for times up to 109 yr in some cases, though only at low inclinations relative to their accompanying planet and over a restricted range of heliocentric eccentricities. These stable areas are well outside the traditional satellite region. Based on these results, we conclude that a primordial population of such objects may still exist in our solar system.