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$\begin{figure} \par\includegraphics[width=11.9cm,clip]{3474F1.ps}\end{figure}$ Figure 1: N-band visibilities and spectra observed for IRAS08002. a) Observed visibilities plotted as a function of wavelength. The errors of the observed visibilities are typically $\pm 10$ -15%, but the error bars are omitted in this panel for the sake of visual clarity. b-d) Visibilities at three representative wavelengths in the N band are plotted as a function of spatial frequency, together with uniform-disk fits. e) Uniform-disk diameter (UDD) obtained by fitting the visibility points of all four data sets is plotted as a function of wavelength. f) Observed spectra of IRAS08002. The absolutely calibrated MIDI spectrum is plotted with the filled circles, while the IRAS LRS is plotted with the open squares.
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In the text

$\begin{figure} \par\includegraphics[width=8.7cm,clip]{3474F2.ps}\end{figure}$ Figure 2: a) Comparison between the SEDs calculated with mcsim_mpi (see Sect. 3.1) and DUSTY for three different optical depths. The effective temperature of the central star and the inner boundary temperature of the dust shell are set to be 3000 K and 1000 K, respectively. The results obtained with DUSTY are represented with the solid, dashed, and dotted lines, while the results obtained with mcsim_mpi are represented with the dots, filled diamonds, and filled triangles. b) Comparison between the temperature distributions calculated with mcsim_mpi and DUSTY. The meanings of the symbols are the same as in the panel a)
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In the text

$\begin{figure} \par\includegraphics[width=8.7cm,clip]{3474F3.ps}\end{figure}$ Figure 3: Comparison between the results obtained with mcsim_mpi and the results of the benchmark tests for $\tau _{V}$ = 100 published in Pascucci et al. (2004). a) Comparison of the SEDs calculated for two different inclination angles. The results of the benchmark tests of Pascucci et al. (2004) are plotted with the solid and dashed lines, while the results obtained with mcsim_mpi are plotted with the filled circles and filled triangles. b) Comparison of the temperature distributions obtained with mcsim_mpi and the benchmark tests. The solid line represents the radial temperature distribution of the benchmark tests predicted for an angle of 2.5 $^\circ$ measured from the equatorial plane. The corresponding temperature distribution obtained with mcsim_mpi is represented with the filled triangles.
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In the text

$\begin{figure} \par\includegraphics[width=8.7cm,clip]{3474F4.ps}\end{figure}$ Figure 4: Axisymmetric disk model consisting of silicate dust alone. The parameters of the model are $\tau _{V}^{\rm sil}$ = 15, $r_{\rm in}$ = 15 $R_{\star }$ (30 AU), $\Theta$ = 50 $^\circ$ , and a radial density distribution proportional to r^-1.4. The model SED and visibilities are calculated for an inclination angle of 30 $^\circ$ (measured from pole-on). a) The observed SED is shown by the open squares (Le Bertre et al. 1990, de-reddened with $A_{\rm V} = 1.5$ ), open triangles (IRAS), and filled triangles (IRAS LRS). The original data of Le Bertre et al. (1990), not corrected for the interstellar extinction, are also plotted with the filled squares. The model SED is represented with the solid line. b) Filled triangles and diamonds: N-band visibilities measured with the 39 m and 46 m baselines (data sets #2 and #3), respectively. Thick and thin lines (solid, dashed, and dotted) represent the visibilities predicted for projected baseline lengths of 39 and 46 m, respectively. The solid, dashed, and dotted lines represent the model visibilities predicted for different position angles (solid line: perpendicular to the symmetry axis of the model intensity distribution, dotted line: parallel to the symmetry axis, dashed line: 45 $^\circ$ with respect to the symmetry axis). See also Sect. 4 and Fig. 6.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{3474F5.ps}\end{figure}$ Figure 5: The best-fit disk model consisting of silicate and amorphous carbon (see Sect. 5.1). The parameters of the model are $\tau _{V}^{\rm sil}$ = 25, $\tau _{V}^{\rm amc}$ = 15, $r_{\rm in}$ = 15 $R_{\star }$ (30 AU), p = 1.6, and $\Theta$ = 50 $^\circ$ . The model SED and visibilities are calculated for an inclination angle of 30 $^\circ$ . See also the legend to Fig. 4 for the references of the symbols. a) Comparison between the observed and model SEDs. b) Comparison between the observed silicate emission spectra and the predicted spectrum. c) Filled triangles and diamonds: N-band visibilities measured with the 39 m and 46 m baselines, respectively. Thick and thin lines (solid, dashed, and dotted) represent the corresponding model visibilities. See the legend to Fig. 4 for the meanings of the different line types. d) The observed uniform-disk diameters are plotted with the filled diamonds. The thick and thin dotted lines represent the uniform-disk diameters predicted for the 39 m and 46 m baselines, respectively, with the baseline vector parallel to the symmetry axis. e)-g) The model visibilities predicted with the baseline vector parallel to the symmetry axis are plotted (solid lines) together with the observed visibilities. See Fig. 1 for the references of the symbols.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{3474F6.ps}\end{figure}$ Figure 6: The mid-infrared images predicted by the best-fit model containing silicate and amorphous carbon dust. In each image, the color scale is normalized with the maximum intensity (excluding the central star) and the minimum intensity set to $3 \times 10^{-2} \times$ maximum intensity (the color scale on the central star is saturated). The model parameters are given in the legend to Fig. 5 as well as in Sect. 5.1. The solid, dashed, and dotted lines in the left panel illustrate the orientation of the baseline vectors used in the visibility calculations.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{3474F7.ps}\end{figure}$ Figure 7: The best-fit disk model consisting of small and large silicate grains (see Sect. 5.2). The parameters of the model are $\tau _{V}^{\rm sil}$ = 25, $\tau _{V}^{\rm SIL}$ = 2.0, $r_{\rm in}$ = 15 $R_{\star }$ (30 AU), p = 1.8, and $\Theta$ = 30 $^\circ$ . The model SED and visibilities are calculated for an inclination angle of 45 $^\circ$ . See also the legend to Fig. 4 for the references of the symbols. a) Comparison between the observed and model SEDs. b) Comparison between the observed silicate emission spectra and the predicted spectrum. c) Filled triangles and diamonds: N-band visibilities measured with the 39 m and 46 m baselines, respectively. Thick and thin lines (solid, dashed, and dotted) represent the corresponding visibilities. See the legend to Fig. 4 for the meanings of the different line types. d) The observed uniform-disk diameters are plotted with the filled diamonds. The thick and thin solid lines represent the uniform-disk diameters predicted for the 39 m and 46 m baselines, respectively, with the baseline vector perpendicular to the symmetry axis. e)-g) The model visibilities predicted with the baseline vector perpendicular to the symmetry axis are plotted (solid lines) together with the observed visibilities. See Fig. 1 for the references of the symbols.
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In the text

$\begin{figure} \par\includegraphics[width=12cm,clip]{3474F8.ps}\end{figure}$ Figure 8: The best-fit disk model consisting of silicate and metallic iron grains (see Sect. 5.3). The parameters of the model are $\tau _{V}^{\rm sil}$ = 20, $\tau _{V}^{\rm Fe}$ = 3.0, $r_{\rm in}$ = 20 $R_{\star }$ (40 AU), p = 1.6, and $\Theta$ = 50 $^\circ$ . The model SED and visibilities are calculated for an inclination angle of 30 $^\circ$ . See also the legend to Fig. 4 for the references of the symbols. a) Comparison between the observed and model SEDs. b) Comparison between the observed silicate emission spectra and the predicted spectrum. c) Filled triangles and diamonds: N-band visibilities measured with the 39 m and 46 m baselines, respectively. Thick and thin lines (solid, dashed, and dotted) represent the corresponding model visibilities. See the legend to Fig. 4 for the meanings of the different line types. d) The observed uniform-disk diameters are plotted with the filled diamonds. The thick and thin dotted lines represent the uniform-disk diameters predicted for the 39 m and 46 m baselines, respectively, with the baseline vector parallel to the symmetry axis. e)-g) The model visibilities predicted with the baseline vector parallel to the symmetry axis are plotted (solid lines) together with the observed visibilities. See Fig. 1 for the references of the symbols.
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In the text