2.5-300 μm laboratory observations of submicron SiC particles as cosmic dust candidates - Borghesi, A.; Bussoletti, E.; Colangeli, L.; Orofino, V.; Guido, M.; Nunziante-Cesaro, S. (Elsevier)
Three different kinds of α-SiC and one β-SiC sample which have undergone the same treatment procedures have been studied morphologically. Their absorption spectra have also been measured in the range 2.5-300 μm. Outside the typical 11.5 μm absorption band, all spectra show an FIR trend which can be fitted by a power law λ^-^γ. The steepness is seen to increase as a function of sample purity. For the highest purity, 99.3%, γ = 1.4. The lowest values are interpreted as being due to the presence of some contaminants in the samples, metallic Fe mainly and also free C and free SiO. β-SiC also shows a λ^-^γ spectrum with γ 1.0, while that measured by Tanabe et al.^ ^7 is found to be characterized by γ = 1.4 again. This difference is tentatively interpreted as being due to a higher purity of the Japanese group sample. The results of our analysis seem to suggest that α-SiC and β-SiC differ morphologically, while their FIR spectra follow a similar λ^-^1^.^4 trend. Astronomical observations at these long wavelengths do not allow any identification of the actual SiC type existing in space which, on the contrary, can probably be identified by analysing the 11.5 μm band.
http://linkinghub.elsevier.com/retrieve/pii/0020-0891(86)90045-X
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