Ablation of Micrometeoroids Simulated in the Laboratory
Abstract
Observations of micrometeoroids entering Earth's atmosphere are used to constrain models of interplanetary dust in the Solar System. Ionization of meteoric matter plays an important role in the detectability of meteors by ground-based radar systems, but the processes by which micrometeoroids ablate by heating up, evaporating, and ionizing are not fully understood. Furthermore, meteoroids ablate through the process of differential ablation, in which more volatile material in the meteoroid will ablate at lower temperatures earlier in the meteor's trajectory than less volatile material. Differential ablation is critical to understand in order to fully characterize meteor ablation, and to understand how and where meteors will deposit material into Earth's atmosphere, thus affecting the atmospheric chemistry. At the University of Colorado, we have been investigating the processes involved in micrometeoroid ablation by creating simulated meteors in the laboratory. Using the University of Colorado's 3 MV hypervelocity dust accelerator, small particles were shot into a gas target holding one of several different gases (air, nitrogen, argon, or carbon dioxide) at a constant pressure. Using the accelerator and gas target facility, the drag, heating, ionization, and differential ablation of simulated meteors have been observed by measuring the slowdown and charge production of particles traveling through the gas target. The measurements indicate that micrometeoroid drag may be more significant than previously thought, which will reduce the heating and ionization of micrometeoroids thereby reducing their detectability by radar observations. Differential ablation has also been observed to occur when minerals are shot into the gas target. For the differential ablation experiments, platinum-coated magnesite and polypyrrole-coated olivine particles were shot into the gas target, and in both cases different constituents of the simulated meteoroids were observed to ablate at different points along the particle's trajectory. These experiments provide critical laboratory data on the physics and chemistry of meteor ablation, allowing for a better understanding of how micrometeoroids interact with planetary atmospheres.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P53E3010D
- Keywords:
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- 2129 Interplanetary dust;
- INTERPLANETARY PHYSICSDE: 6213 Dust;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6245 Meteors;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6265 Planetary rings;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS