Structure of possible long-lived asteroid belts

Abstract

High-resolution simulations are used to map out the detailed structure of two long-lived stable belts of asteroid orbits in the inner Solar system. The Vulcanoid belt extends from 0.09 to 0.20 au, though with a gaps at 0.15 and 0.18 au corresponding to de-stabilizing mean motion resonances with Mercury and Venus. As collisional evolution proceeds slower at larger heliocentric distances, km-sized or larger Vulcanoids are most likely to be found in the region between 0.16 and 0.18 au. The optimum location to search is at geocentric ecliptic longitudes 9° ≤ |ℓg| ≤ 10° and latitudes |βg| < 1°. Dynamically speaking, the Earth-Mars belt between 1.08 and 1.28 au is a stable repository for asteroids on nearly circular orbits. It is interrupted at 1.21 au owing to the 3:4 commensurability with the Earth, while secular resonances with Saturn are troublesome beyond 1.17 au. These detailed maps of the fine structure of the belts can be used to plan search methodologies. Strategies for detecting members of the belts are discussed, including the use of infrared wide-field imaging with VISTA, and forthcoming European Space Agency satellite missions such as GAIA and BepiColombo.