Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra

Details Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra

Jul 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010a%26a...517a..60k&link_type=abstract

Astronomy and Astrophysics, Volume 517, id.A60

Astronomy and Astrophysics

Astrophysics

2

Minor Planets, Asteroids: General, Methods: Laboratory, Techniques: Spectroscopic

Scientific paper

Context. The surfaces of airless bodies in the Solar System are continuously altered by the bombardment of micrometeoroids 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, as well as a “degrading” of absorption features. Aims: We studied the changes induced by energetic ion irradiation in the ultraviolet-visual-near-infrared (UV-Vis-NIR) (0.2-0.98 μm) reflectance spectra of targets selected to mimic the surfaces of airless bodies in the inner Solar System. Our chosen targets are olivine pellets, pure or covered by an organic polymer (polystyrene), which is transparent before irradiation. Polystyrene is used as a template for organic matter of low volatility that can be present on asteroidal surfaces. Moreover we measured the changes induced by ion irradiation in the absorption coefficient of the polymer. The purpose was to have a tool to better compare laboratory with observed spectra and distinguish between planetary objects with pure silicate surfaces and those whose surface is covered by organic matter exposed to cosmic ion bombardment. Methods: The samples were irradiated in vacuum, at room temperature, with 200 keV protons or 200-400 keV argon ions. Before, during, and after irradiation diffuse reflectance spectra were acquired. Polystyrene films were also deposited on quartz substrates and irradiated while transmittance spectra were recorded. Results: We measured the variations of the absorption coefficient of polystyrene as a function of ion fluence. We showed that after ion irradiation the diffuse reflectance spectra of the 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. Conclusions: The results obtained for pure olivine extend to the UV the spectral range of previous experiments. The data concerning the absorption coefficient of polystyrene are available on our web site (http://web.ct.astro.it/weblab/dbindex.html) and can be used to compare laboratory with astronomical spectra. This will possibly allow us to obtain information about organic matter on the surface of a given object, as well as on the relevance of the exposure to cosmic ions (space weathering).
Data table is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/517/A60

Affiliated with

Also associated with

No associations

Rating

Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Space weathering of asteroidal surfaces. Influence on the UV-Vis spectra will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1642033