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:
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: J. Weiprecht Feb. 2020