The Earth's Dust Belt: Fact or fiction?: 4. Sunlight-pressure air-drag capture

Abstract

We investigated the contribution to the earth's dust belt that stems from the trapping of particles into long-lifetime bound geocentric orbits by the combined action of air drag and sunlight pressure. This concentration mechanism is of significance only if the speed of a substantial fraction of the dust particles entering the earth's sphere of influence is of the order of 1 km/sec or less. The dust-particle flux will then exhibit a broad peak at an altitude of about 0.5 earth radii and will be of the order of 102 or more times greater than the flux at the boundary of the earth's sphere of influence. By considering a more realistic initial distribution of dust-particle orbits, we conclude that our theoretical analyses lend little support to the supposition that the earth is a very effective entity for concentrating interplanetary dust particles.