The measurements of optical properties of candidate materials for circumstellar and interstellar dust in far-infrared region and application to infrared astronomy

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Since the observation of ISO (Infrared Space of Observatory), crystalline silicates were detected every where in circumstellar of young objects and evolved objects. These facts are contradicts against the traditional idea of amorphous dust. In order to make clear the evolution of dust material and mass quantity of dust, the good data of optical properties of various materials are needed. But, only few data can be published. Crystalline silicates are Mg-rich such as forsterite Mg_2SiO_4 and enstatite MgSiO_3. Cooling olivine and pyroxene particles to liquid helium temperature the peak positions are shifted to shorter wavelength and peaks become sharper. This is the same results of observation, which the spectra showed the sharp peaks and circumstellar dust exist in low temperature as several 10 K. In universe, Mg elements and Fe elements are equally exist. So, it is very important to study how the spectra depend on Mg/Fe ratio. With our measurements of infrared spectra of olivine and pyroxene, the spectra were depend on Mg/Fe ratio, and peak positions are shifted to longer wavelength as Mg content decreases. Particularly, end members are very sensitive to Mg/Fe ratio, and peak shifts are drastically changed as this ratio. We detected diopside around evolved objects comparing with observed broad band at about 65 μm and laboratory measured data. This broad band was thought to originate to water ice, but water ice shows peak at around 62 μm even cooled to various temperature. Since our detected diopside, many workers noticed both of high and low temperature condensation minerals, and some group detected carbonate minerals such as calcite and dolomite. Recently, many new discover of minerals according to condensation theory are showed, and identification of observed bands and evolution of materials are very interesting.