All Figures

$\begin{figure} \par\includegraphics[width=7cm,clip]{0312_f1a.eps}\hspace*{4mm} \... ...1c.eps}\hspace*{4mm} \includegraphics[width=7cm,clip]{0312_f1d.eps} \end{figure}$ Figure 1: Overview of the transmission spectra of a) talc, b) picrolite, c) montmorillonite, and d) chamosite in the 25-110 $\mu$ m region. The dotted lines refer to measurements at room temperature, while the solid lines denote the cryogenic measurements performed at 10 K. For the latter, the spectra are shifted by -0.1 for clarity. For montmorillonite, the room-temperature data have been measured without cryostat. For consistency, we display the 200 K spectrum here.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f2.eps} \end{figure}$ Figure 2: Mass absorption coefficient in the FIR range for talc at different temperatures. The data have been measured at an enhanced powder concentration of 1:10. Note the change in width and band position of the $\sim$ 98 $\mu$ m band due to the cooling of the sample.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f3.eps}\end{figure}$ Figure 3: Mass absorption coefficient spectra showing the $\sim$ 76 $\mu$ m picrolite band for temperatures of 300 K and 10 K. The thin lines represent the original data - affected by fringes - while the bold lines denote the result of a 5-point-averaging procedure.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f4.eps}\end{figure}$ Figure 4: Mass absorption coefficient spectra of the montmorillonite sample in the FIR range. The inset displays the 10 K spectrum again on a linear scale to emphasize the individual absorption bands.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f5.eps}\end{figure}$ Figure 5: Combined transmission spectrum of chamosite particles embedded in a KBr and a PE pellet at an identical column density of 0.3 mg/cm². The spectra were merged at 16.7 $\mu$ m.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f6.eps}\end{figure}$ Figure 6: Mass absorption coefficient spectra of the chamosite sample in the FIR range. The spectra are a combinations of measurements at two different column densities (see text). The fringes in the original data have been removed by a sliding average method used up to a wavelength of about 200 $\mu$ m and by Lorentzian fitting for the 277 $\mu$ m band. The structure at about 130 $\mu$ m is due to imperfect compensation of a PE absorption band.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f7.eps}\end{figure}$ Figure 7: Comparison of the mass absorption coefficients of three of the hydrous silicates measured at 10 K. Picrolite is not shown because the pellet cooled to 10 K had too low a column density to allow a derivation of the low (comparable to talc at room temperature) continuum absorption values. Picrolite has its longest wavelength band at 76 $\mu$ m at 10 K, see Fig. 3.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f8.eps} \end{figure}$ Figure 8: The ISO spectrum of HD 142527 (solid lines) compared to the emission spectra of cold montmorillonite (dashed line) and talc dust (dotted line). The latter have been calculated by multiplying the mass absorption coefficients $\kappa$ of montmorillonite and talc at 10 K with a blackbody function for the best-fitting temperature, T=38 K. Featureless dust ( $\kappa _{\rm FIR} \propto 1/\lambda$ ; dash-dotted line) is an alternative carrier of the broad emission in the 100 $\mu$ m region.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f2.eps} \end{figure}$	Figure 2: Mass absorption coefficient in the FIR range for talc at different temperatures. The data have been measured at an enhanced powder concentration of 1:10. Note the change in width and band position of the $\sim$ 98 $\mu$ m band due to the cooling of the sample.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f3.eps}\end{figure}$	Figure 3: Mass absorption coefficient spectra showing the $\sim$ 76 $\mu$ m picrolite band for temperatures of 300 K and 10 K. The thin lines represent the original data - affected by fringes - while the bold lines denote the result of a 5-point-averaging procedure.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f4.eps}\end{figure}$	Figure 4: Mass absorption coefficient spectra of the montmorillonite sample in the FIR range. The inset displays the 10 K spectrum again on a linear scale to emphasize the individual absorption bands.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f5.eps}\end{figure}$	Figure 5: Combined transmission spectrum of chamosite particles embedded in a KBr and a PE pellet at an identical column density of 0.3 mg/cm². The spectra were merged at 16.7 $\mu$ m.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0312_f7.eps}\end{figure}$	Figure 7: Comparison of the mass absorption coefficients of three of the hydrous silicates measured at 10 K. Picrolite is not shown because the pellet cooled to 10 K had too low a column density to allow a derivation of the low (comparable to talc at room temperature) continuum absorption values. Picrolite has its longest wavelength band at 76 $\mu$ m at 10 K, see Fig. 3.
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