Grant: Discovery Grants Program - Individual

The research will combine laboratory based measurements and observations using 'night vision' (image intensifiers) and charge coupled device (CCD) digital cameras to study how meteors ablate and produce light in the Earth's atmosphere. The laboratory based research will employ a pulsed laser to vaporize small regions of meteorites. The short duration light produced following ablation will be studied using synchronized digital cameras, digital spectroscopes and photometers. A scanning electron microscope (SEM) will be used to precisely measure the mass of meteorite material vaporized. By relating this mass to the light and laser energies, we will obtain an estimate of the luminous efficiency factor. The luminous efficiency factor is the ratio of the light produced to the kinetic energy of impinging atmospheric molecules. Since most meteoroid masses are estimated by integrating the light produced by the meteor and assuming a value for the luminous efficiency value, mass flux estimates, and the associated space risk, depends critically on this value. We will use energy dispersive X-ray spectroscopy (EDS) to measure the abundance of elements before and after laser ablation. We will determine if meteors ablate in a chemically differential manner, that is do more volatile elements such as sodium or carbon ablate first. Meteoroids from comets are believed to have been little altered since the formation of the solar system 4.6 billion years ago. Most meteoroids are dustballs, collections of thousands of individual dust grains held together by a more volatile 'glue'. Our differential ablation work will test the premise that carbon may be this 'glue'. We will use telescopic optics with the CCD cameras and spectrometers to search for evidence of dustball fragmentation. We will continue to explore this question of contamination of cometary nuclei by deep impact of high velocity meteoroids. We will use dual telescopes and CCD detectors and spectrometers in order to search for meteoroid impacts on the moon, and develop models for the risk of secondary ejecta to space operations on the surface of the moon.