Secondary processing of chondrules and refractory inclusions (CAIs) by gasdynamic heating

The aerodynamic heating of meteoric particles on entering the atmosphere of a planet is explained by a theoretical model. The effects of melting, vaporization and heat conduction into the interior of the particle are incorporated in the model. The model is used for the interpretation of the properties of chondrule rims. The fractionation of the low-melting-temperature component in the outer part of the chondrule, before the rim formation, causes the formation of true melt rims by atmospheric entry. The different encounter conditions and chondrite types are indicated by the existence of thermal alteration effects in UOC chondrites.