““Learning about the degree of aqueous alteration of NEOs from ...

PRELIMINARY RESULTS
• Significant differences in the reflectance spectra of CCs reflects a
remarkable compositional diversity
– The ATR technique is very sensitive to OH and other bonds absorption bands, but
also provides information about organic features
• CC groups exhibit components with distinctive abundance ratios
– Chondrules are the abundant ingredients, but they vary in average size and
proportions, such as the Ca-Al rich inclusions (CAIs) and other components
– Metal grain abundances are highly variable from being almost absent to ubiquitous
depending of the chondrite group, and their presence inside the chondrules or in the
matrix has direct implications to reflectance
• Laboratory analyses of the reflectance of Antarctic CCs provide useful
information for remote characterization of Marco Polo-R target
– An accurate IR spectrum provides very significant features and
absorption bands that have direct application:
• The depth of the OH bands are directly related with the extent of aqueous alteration:
how much water is bounded in phyllosilicates
• The distinctive features allow to make reasonable distinction of the different surface
mineralogy (if it is a complex breccia)
• Consequently, IR spectroscopy of the target in a small scale is essential for sampling
pristine carbonaceous materials (Marco Polo-R goal)