Comet Dust from Airborne Leonid Storm Observations

For the past five years, rare Leonid meteor storms offered unique access to cometary dust by spectacular manifestations of recently ejected dust grains, which could be observed by exceptional meteor observing techniques. The final storms, those of November 19, 2002, measured the dust distribution in a comet dust trail far from the position of the comet itself. The measured spatial and particle size distribution of dust still reflect the conditions of ejection and the influence of radiation pressures on the grains, and provide unique insight into the dust-to-ice ratio in cometary matter. The meteor observations also provide data on meteoroid composition and morphology for grains of mm-cm size that are larger than studied by Stardust. The meteoroids derive from comet 55P/Tempel-Tuttle and were ejected in 1866 and 1767, respectively, only 4 and 7 orbits ago. Both meteor storms were well observed from two research aircraft operated by NASA and USAF. This final mission in the Leonid Multi-Instrument Aircraft Campaign provided an international team of 38 researchers prime viewing without interference of moonlight and with a radiant position high in the sky. En route from Madrid, Spain, to Omaha, Nebraska, the storms were observed to peak at 04:06 UT and 10:47 UT, respectively. A range of spectroscopic and imaging techniques was used to measure the physical properties and composition of the meteors. Apart from accurate flux profiles, highlights include the first near-IR spectra of meteors, high frame-rate (1000/s) images, mid-IR spectra of persistent trains, as well as spectacular video images with a background of aurora. Introduction: We use Fischer-Tropsch type (FTT) synthesis to produce hydrocarbons by hydrogenating carbon monoxide via catalytic reactions. The products of these reactions have been studied using 'natural' catalysts [1] and calculations of the efficiency of FTT synthesis in the Solar Nebula suggest that these types of reactions could make significant contributions to the composition of material near three AU [2]. We coat Fe-silicate grains with organic material using FTT synthesis to simulate the chemistry in the early Solar Nebula [3]. In our experimental setup, we roughly model a nebular environment where grains are successively transported from hot to cold regions of the nebula. In other words, the starting gases and FTT products are continuously circulated through the grains at high temperature with intervals of cooling (see Fig 1). Organics generated in this manner could represent the carbonaceous material incorporated in comets and meteorites. We analyze the …