Optical properties of candidate minerals for circumstellar dust in the UV - Far infrared region and application for Infrared Astronomy

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For various candidates materials for circumstellar dusts, we investigated the temperature effects on infrared spectra of fine particles. Especially, as for temperature effects on spectra of olivine particles cooling down from room temperature to about 10 K, the intensity and half width of each peak became strong and narrow, respectively, and the position of each peak shifted to shorter wavelength. These tendencies were gentle in mid infrared region, but were very distinct in far infrared region. In particularly for the case of forsterite, the position and half width of 49 and 69μm were shown to be become the temperature indicator. That is, any observer can know the dust temperature from the observed position and half width in circumstellar or interstellar region.We synthesized olivine samples near end member of forsterite and made clear that the 49 and 69μm peak changed drastically according to the Fe content. Further we synthesized silicate crystalline including Ca, Na, Al elements, a … More nd the correlation between peak position and composition was made clear. Amorphous silicates with chondritic components were synthesized by Sol-Gel method, and the process to crystallization was made clear studying the change of infrared spectra after annealing.As for bulk sample of forsterite, we can obtained the satisfactory optical constants for each axis from each measured reflectance in mid and far infrared. Further, cooling the bulk sample of forsterite continuously to about 10 K, the reflectance were measured in mid and far infrared region for 3 axis. Then, we obtained the optical constants for each axis from the reflectance at many low temperature. As for the reflectance of 69μm band, the intensity become 3 times at 10 K compared to at room temperature. Another peaks at far-infrared also showed similar tendencies. We made clear the optical constants for each axis depend on temperature. From the optical constants, anyone can calculate the spectra in various shape such as needle, oblate, prorate and pale. The shape effects were ascertained in laboratory in the case of ellipse and cauli flower of forsterite. Less