Morphological, chemical and mineralogical studies of cosmic dust

Abstract

Significant numbers of 5 un-1 mm particles of interplanetary dust have been collected and subjected to laboratory analysis. The extraterrestrial origin of selected samples has been established by detection of space-exposure effects such as implanted solar wind and tracks of solar cosmic rays. The collected samples should contain both cometary and asteroidal particles. The asteroidal component is probably a representative sample of typical main-belt asteroids. The elemental composition of the majority of particles is similar to Cl and CM chondrites. Most particles can be grouped into one of two general classes, those that contain hydrated minerals and those that are anhydrous. Some of the hydrated particles may be samples of CI/CM matrix whereas most of the anhydrous particles are clearly unrelated to any known chondrite class. Some of the anhydrous particles are very porous aggregates that at least superficially resemble models of cometary meteors. Future studies of cosmic dust will probably lead to criteria for distinguishing between asteroidal and cometary particles.