Optical Data of Cosmic Dust Analogues
Laboratory Astrophysics Group of the AIU Jena
Additional information about natural und annealed spinel:
A natural spinel from Burma was investigated before and after annealing (1h at 950°C).
It was a dark-red, octahedral spinel crystal from Burma with face diametres of 3 mm.
The optical constants were obtained by oscillator fit analysis to the reflection spectra.
Reflection spectra of natural Spinel (ASCII)
Reflection spectra of annealed natural Spinel (ASCII)
By doing oscillator fit analysis, the optical constants have been derived:
Mg Al(2) O(4) (natural)
Mg Al(2) O(4)
(natural, annealed 1h, 1223 K)
Using these data, mid-IR emissivity of spinel spheres in the Rayleigh limit have been calculated.
Note the loss of the 17 micrometre emissivity peak after annealing:
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Last modified: Dirk Fabian, July 2001