The physical properties of meteorites

摘要

Meteorites provide vast amounts of information on the make up and history of the solar system. Physical properties are a critical component to provide this information. This is a review of the physical properties of meteorites that have been conducted over the past approximately fifty years. Since the late 1950s, the understanding of physical properties has grown greatly. The density, porosity, and magnetic susceptibilities of hundreds of meteorites have been analyzed. More is known about the mineralogical and chemical compositions of meteorites, while the physical properties have not been as well characterized. Other properties summarized are specific gravity, strength (compressive and tensile), elastic wave velocity, heat capacity, thermal conductivity, electrical resistivity, albedo, and emissivity. For most stony meteorite types the average densities, between 3 and 4 g/cm(3), and porosities, below 10%, have not changed significantly over the 50 years. The compressive strengths of meteorites follow the expected trends of their material and cover a wide range from the weak Tagish Lake, 0.25 MPa, to the strong Canyon Diablo, 411 MPa. Thermal conductivity has mostly been studied from 200 to 300K, with most stony meteorites having conductivities less than 5 W/(m-K). The studies of physical properties of meteorites provide information for a better understanding of meteor behavior in the atmosphere, model characteristics of parent bodies, and effectiveness of different deflection methods for potentially hazardous objects.