VIS-NIR REFLECTANCE MICRO-SPECTROSCOPY OF IDPs

Visible near-infrared (Vis-NIR) reflectance spectroscopy is a powerful nondestructive technique allowing the parent bodies identification of cosmomaterials such as meteorites, micrometeorites, and interplanetary dust particles (IDPs) studied in the laboratory. Previous studies showed that meteorites do not represent the full diversity of the solar system small bodies. We present here an experimental setup we developed for measuring Vis-NIR microspectroscopy of individual IDPs. We acquired diffuse Vis-NIR reflectance spectra of 15 particles ranging 7-31 mu m in size. We discuss the requirements, the abilities, as well as the limitations of the technique. For sizes smaller than 17 mu m, the slopes increase with decreasing particles sizes, while for sizes larger than 17 mu m, the slopes are randomly distributed. The visible reflectance levels do not appear to be affected by the size of the IDPs, and show a bimodal distribution. Among the studied particles, we identified an IDP (L2079C18) exhibiting a feature at 0.66 mu m, which is similar to the one observed by remote sensing on the surface of hydrated asteroids. This is the first detection of a hydration band in the reflectance spectrum of an IDP that could indicate a possible link between hydrated IDPs with hydrated asteroid surfaces.