Noble Gases in Stratospheric Dust Particles: Confirmation of Extraterrestrial Origin

Noble gas elemental and isotopic ratios were measured in a group of 13 ``chondritic'' stratospheric dust particles. Neon and argon are present in ``solar'' proportions; xenon appears to be dominated by contributions from ``planetary'' sources. The apparent xenon concentration is higher than that measured in any bulk meteorite, approaching the concentration found in the noble gas-rich, acid-insoluble residues from carbonaceous chondrites.