ABSTRACT
In a consortium analysis of a large particle captured from the coma of comet 81P/Wild 2 by the Stardust spacecraft, we report the discovery of a field of fine-grained material (FGM) in contact with a large sulfide particle. The FGM was partially located in an embayment in the sulfide. As a consequence, some of the FGM appears to have been protected from damage during hypervelocity capture in aerogel. Some of the FGM particles are indistinguishable in their characteristics from common components of chondritic-porous interplanetary dust particles (CP-IDPs), including glass with embedded metals and sulfides (GEMS) and equilibrated aggregates (EAs). The sulfide exhibits surprising Ni-rich lamellae, which may indicate that this particle experienced a long-duration heating event after its formation but before incorporation into Wild 2.
ABSTRACT
A Peltier-based freeze-thaw device for the disaggregation of meteorite or other rock samples is described. Meteorite samples are kept in six water-filled cavities inside a thin-walled Al block. This block is held between two Peltier coolers that are automatically cycled between cooling and warming. One cycle takes approximately 20 min. The device can run unattended for months, allowing for â¼10 000 freeze-thaw cycles that will disaggregate meteorites even with relatively low porosity. This device was used to disaggregate ordinary and carbonaceous chondrite regoltih breccia meteorites to search for micrometeoroid impact craters.