Density, chemistry, and size distribution of interplanetary dust

Depth/diameter ratios measured for 98 craters in lunar glass targets reveal a broad distribution with a single strong peaking between 0.55 and 0.8. The measured values indicate a mean meteoroid density greater than 1 g/cu cm and probably less than 4 g/cu cm. Microprobe analyses show that typical glass pit liners on silicate targets contain only approximately 0.1% or less of meteoritic material. The size-frequency distribution of meteoroids was analyzed for a fractured glass surface of 60095, and a very steep size distribution of submicron meteoroids is indicated. As in the case of 15205, a dip at approximately 5 micron in the size-frequency distribution is detected.