AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Single Particle Studies of Atmospheric Meteor Ablation
DANIEL CZICZO, Daniel Murphy, MIT
Abstract Number: 435 Working Group: Extraterrestrial Aerosols: from Mars to Titan and Beyond
Abstract Single-particle analyses of stratospheric aerosol show that about half of the particles contain meteoritic components. Although predominantly sulfuric acid and water by mass, a few weight percent, including 0.5 to 1.0 iron by mass, can be attributed to an extraterrestrial flux to the atmosphere. This material likely ablated at ~100 km altitude, condensed and coagulated to form meteoritic ‘smoke’ particles, and then acted as condensation centers for sulfuric acid and water as they gravitationally settled through the stratosphere. The overall mass of material can be used to infer an extraterrestrial flux of 8 to 28 gigagrams per year. Component ratios, such as sodium/iron, magnesium/iron and calcium/iron can be compared to common meteorites and imply that the fraction of material that is ablated must lie at the low end of previous estimates. This result suggests the extraterrestrial component that resides in the mesosphere and stratosphere is not of chondritic composition but is instead enriched in volatiles and correspondingly depleted in more refractory components.