Polyaromatic Units Set the Albedo of Dark Extraterrestrial Materials

Primitive extraterrestrial materials are generally dark, a characteristic often associated with the presence of polyaromatic organic material and/or sulfides. We show in this study that the reflectance level measured at 0.55 μ m of IDPs and some meteorites is correlated to the degree of graphitization of the polyaromatic organic matter. The reflectance level of the primitive surfaces therefore allows us to obtain information on the polyaromatic organic material present on the surface of solar system small bodies observed by remote sensing or visited by space missions. We discuss our results in view of the sample return missions Hayabusa2 and OSIRIS-REx.