Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2020.113722]
1Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, 91405 Orsay, France
2Division of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, Japan
3SOLEIL Synchrotron, Gif-sur-Yvette, France
Solar wind ion irradiation continuously modifies the optical properties of unprotected surfaces of airless bodies in the Solar System. This alteration induces significant biases in the interpretation of the spectral data obtained through remote sensing, and it impedes a correct estimation of the composition of the sub-surface pristine materials. However, as the alteration of the surface is a function of time, an in-depth understanding of the phenomenon may provide an original way to estimate the weathering age of a surface. Laboratory experiments show that mid- and far-IR bands are very sensitive to space weathering, as they are significantly modified upon irradiation. These bands can thus constitute a reliable proxy of the time-bound effects of irradiation on an object. We show that the detection of irradiation effects is within the reach of IR spectral resolution of the OSIRIS-REx mission and of the future James Webb Space Telescope. Our results provide a possible evidence for space weathering effects in the IR spectrum of asteroid 101955 Bennu measured by OTES/OSIRIS-REx.