Seeking Unbiased Collections of Modern and Ancient Micrometeorites

Abstract

Micrometeorites are sub-millimeter-sized extraterrestrial particles that survive atmospheric entry. An unbiased collection of micrometeorites should contain samples of all of the dust-producing objects in the solar system. However, because of low concentrations and rapid weathering in terrestrial environments, unbiased collections are difficult to find. Additionally, most particles have been severely heated during atmospheric entry, and the resulting changes must be understood to derive compositional information about the parent micrometeoroids. Large modern collections that can be characterized by the flux, size distribution, and micrometeorite compositional types can help constrain heating models that predict how micrometeorites are heated while entering the Earth's atmosphere. These collections can also be used as a reference to deduce the effects of weathering on collections of ancient micrometeorites.