Space weathering of asteroidal surfaces . Influence on the UV-Vis spectra
Abstract
The surfaces of airless bodies in the Solar System are continuously altered by micrometeoroids bombardment and irradiation by solar wind, flares and cosmic particles. Major effects of this process - space weathering - are darkening and "reddening" of the spectra of surface materials. We have studied the changes induced by energetic ion irradiation, in the UV-Vis-NIR (0.2-0.98 mu m) reflectance spectra of targets selected to mimic the surfaces of airless bodies in the inner Solar System. Chosen targets are olivine pellets, pure or covered by a transparent organic polymer (polystyrene). We have also measured the changes induced by ion irradiation in the absorption coefficient of the polymer. We have measured the variations of the absorption coefficient (0.25-0.98 mu m) of polystyrene as a function of ion fluence. The diffuse reflectance spectra of irradiated samples covered by organics exhibit a much more significant variation than those of pure silicates. The spectra of targets made of olivine plus polystyrene can be fitted by using the measured absorption coefficient of polystyrene.
- Publication:
-
Memorie della Societa Astronomica Italiana Supplementi
- Pub Date:
- 2011
- Bibcode:
- 2011MSAIS..16..130K
- Keywords:
-
- asteroids;
- methods: laboratory;
- techniques: spectroscopic