| タイトル | Laboratory Measurements of Celestial Solids |
| 本文（外部サイト） | http://hdl.handle.net/2060/19980017812 |
| 著者（英） | Beckwith, S. V. W.; Sievers, A. J. |
| 著者所属（英） | Cornell Univ. |
| 発行日 | 1997-01-01
1997 |
| 言語 | eng |
| 内容記述 | Our experimental study has focused on laboratory measurements of the low temperature optical properties of a variety of astronomically significant materials in the infrared and mm-wave region of the spectrum. Our far infrared measurements of silicate grains with an open structure have produced a variety of unusual results: (1) the low temperature mass opacity coefficient of small amorphous 2MgO(central dot)SiO2 and MgO(central dot)2SiO2 grains are many times larger than the values previously used for interstellar grain material; (2) all of the amorphous silicate grains studied possess the characteristic temperature dependent signature associated with two level systems in bulk glass; and (3) a smaller but nonzero two level temperature dependence signature is also observed for crystalline particles, its physical origin is unclear. These laboratory measurements yield surprisingly large and variable values for the mm-wave absorption coefficients of small silicate particles similar to interstellar grains, and suggest that the bulk absorptivity of interstellar dust at these long wavelengths will not be well known without such studies. Furthermore, our studies have been useful to better understand the physics of the two level absorption process in amorphous and crystalline grains to gain confidence in the wide applicability of these results. |
| NASA分類 | Optics |
| レポートNO | NASA/CR-97-206774
NAS 1.26:206774 |
| 権利 | No Copyright |
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