Vis–NIR Reflectance Microspectroscopy of IDPs

Romain Maupin,Cateline Lantz,Rosario Brunetto,Pierre Vernazza,Alice Aléon-Toppani,Zahia Djouadi

doi:10.3847/psj/abbb98

Abstract

Abstract 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 μm in size. We discuss the requirements, the abilities, as well as the limitations of the technique. For sizes smaller than 17 μm, the slopes increase with decreasing particles sizes, while for sizes larger than 17 μm, 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 μm, 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.

Highlights

Asteroids and comets are the most primitive objects containing valuable clues about the physicochemical conditions of the early solar system
We find chondritic porous interplanetary dust particles (IDPs) (CP-IDPs) with a porosity as high as 70% and a mineralogy characterized by anhydrous silicates
The obtained reflectance spectrum depends on the position of the micrometric collection spot on the surface of the sample

Summary

Introduction

Asteroids and comets are the most primitive objects containing valuable clues about the physicochemical conditions of the early solar system. Vis–NIR reflectance measurements are often used to identify their parent bodies (e.g., McCord et al 1970; Burbine & Binzel 2002 and references therein; Clark et al 2011). Meteorites are not representative of asteroids B-, C-, Cb-, and Cg-types, nor comets such as JFCs (Vernazza et al 2015). Meteorite collections are affected by biases believed to be largely due to injection mechanisms into the inner solar system, mainly controlled by the Kirkwood gaps (Kirkwood 1891), and due to atmospheric entry survival. Identification of their parent bodies remains challenging

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Conclusion