Asteroid surfaces: irradiation and VIS-IR micro-spectroscopy in the laboratory

Primitive extraterrestrial materials, such as meteorites and dust collected by sample return missions, are characterized by a large compositional heterogeneity at different scales. This heterogeneity has been observed in the laboratory by different techniques. Among these, micro-IR spectroscopy has the advantage of being totally non-destructive and allowing direct comparison with astronomical observations. With the development of Focal Plan Array (FPA) detectors, IR mapping with high spatial resolution and IR tomography is now possible with a short acquisition time. In this presentation I will show some recent results of FTIR spectral imaging experiments on different extraterrestrial materials, obtained at the SMIS beamline of the Synchrotron SOLEIL (France), and the implementation of an analytical protocol for future sample return missions (in particular Hayabusa 2, JAXA).
In the second part, I will focus on laboratory spectroscopy to study asteroid space weathering. I will present new VIS-IR spectral imaging data of ion irradiated meteorites, simulating solar wind irradiation of asteroid surfaces. Together with direct evidence of weathering of particles from asteroid Itokawa collected by the Hayabusa mission, these results provide a fundamental contribution to the spectral interpretation of asteroid observations, to establish a solid asteroids-meteorites link, and to understand the energetic processes affecting the surfaces of minor bodies. Spectral trends confirm that solar wind is an efficient source of weathering, and that a number of rejuvenating processes efficiently counterbalance the fast weathering timescales.

31/01/2017 - 12:30
Dr. Rosario Brunetto
Institut d'Astrophysique Spatiale, CNRS/Université Paris Sud, Orsay, France