Electrostatic dust levitation near asteroid Itokawa

Abstract

A plasma sheath is created when the solar wind and solar UV radiation interact with the surface of airless planetary bodies, such as the Moon and asteroids. It has been hypothesized that, due to the low gravity of these bodies (as much as 5 orders of magnitude smaller than Earth's gravity), small dust grains may levitate in the plasma sheaths. Observational evidence for planetary dust levitation is weak: Surveyor horizon glow observations from the Moon have been attributed to zodiacal light after re-analysis. and levitation is one of several possible explanations for the ‘dust ponds’ on the asteroid Eros. However, electrostatic dust levitation has been observed in the lab. Additionally, we have shown that dust levitation is possible (and that stable levitation can occur) near asteroids using numerical simulations with simplified asteroid shape and plasma models.