Quasi-satellite of Venus - Asteroid 2002 VE68

A quasi-satellite is an object in a 1:1 orbital resonance with its planet that stays close to the planet over many orbital periods.

A quasi-satellite's orbit around the Sun takes exactly the same time as the planet's, but has a different eccentricity (usually greater). When viewed from the perspective of the planet, the quasi-satellite will appear to travel in an oblong retrograde loop around the planet.

In contrast to true satellites, quasi-satellite orbits lie outside the planet's Hill sphere, and are unstable. Over time they tend to evolve to other types of resonant motion, where they no longer remain in the planet's neighbourhood, then possibly later move back to a quasi-satellite orbit, etc.

Asteroid 2002 VE68 is a quasi-satellite of Venus. It was discovered on November 11, 2002, by Lowell Observatory Near-Earth-Object Search (LONEOS).

Stats

Asteroid Family Group: Aten asteroid

Diameter: 210 - 470 m

Semi-major axis: 0.724 AU (same as Venus)

Rotation: 13.5 hours


The asteroid 2002 VE68 is currently a quasi-satellite of Venus, the first object of this dynamical class to be discovered, and is also the first known co-orbital companion to Venus.

This asteroid is also a Mercury grazer and an Earth crosser; it seems to have been co-orbital with Venus for only the last 7000 years, and is destined to be ejected from this orbital arrangement about 500 years from now. During this time, its distance to Venus has been and will remain larger than about 0.2 AU.

It has a high eccentricity (~ 0.4) and inclination (~ 9°). Consequently the maximum distance of the asteroid from the Sun is near that of the Earth and the minimum distance is smaller than the aphelion of Mercury.

From the evolution of the orbit of this object, it may have been a near-Earth asteroid, which, some 7000 yr ago, was injected into its present orbit by the action of the Earth.