All Figures

$\begin{figure} \par\includegraphics[width=7cm,angle=0]{4463fig1.eps}\end{figure}$ Figure 1: Radio flux densities of IRC+10216 from 1991 June 1 to 1993 June 8 (second panel from top) compared to that of the calibrator 0953+254 (top panel). For both sources the X-, U-, and K-band integrated flux densities from Gaussian fits are plotted bottom to top. Note the different flux density scales. Error bars represent the quadratic sum of formal fitting errors and estimates of the errors due to absolute flux density calibration (10, 15, and 20% for the X-, U-, and K-band data points). In the IRC+10216 panel, the solid lines represent the results of the model calculations described in the text. The third to fifth panels from top show K-, U- and X-band residuals in percent-for each epoch the flux density predicted by the model was subtracted from the measured value and divided by the model value. X-, U-, and K-band data points are represented as crosses, squares, and circles, respectively. In all panels the same time range is shown. The abscissa gives Julian day number in the top panel and infrared (L'-band) stellar phase, $\Phi$ , in the others. The date of maximum infrared light ( $\Phi =0$ ) was calculated from the value determined by LeBertre 1992 (JD 2447483), using his period of 649 d. The lowermost panel represents the L'-band ( $3.76~\mu$ m) light curve converted to kJy units (see Fig. 2k of Le Bertre 1992).
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In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{4463fig2.eps} \end{figure}$ Figure 2: Interferometric flux densities of IRC+10216 from cm to sub-mm wavelengths. The X-, U-, and K-band cm-wave data points are the weighted averages of data from six epochs (see Table 1). These error bars are quadratic sums of formal uncertainties and absolute calibration errors, which are assumed to be 10, 15, and 20% for the X-, U-, and K-band data, respectively. The error bars of the mm and submm wavelength data are discussed in the text. The straight line has a slope of 2.0, the blackbody value. A least squares fit to all the shown data delivers a slope of $1.96\pm 0.04$ .
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In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{4463fig3.eps} \end{figure}$ Figure A.1: Spectral energy distribution for IRC+10216. Data (squares): J- to M-band from Le Bertre (1987); 12 to 100 $\mu$ m from IRAS; 450 $\mu$ m from Young et al. (2004) for 2'' beam; 1.24 mm fluxes from Lucas & Guelin (1999), lower point for $1\hbox{$.\!\!^{\prime\prime}$ }6$ beam, upper point for total envelope; 88% of the total 3 mm flux (same authors) come from the inner 2 $\hbox{$.\!\!^{\prime\prime}$ }$ 4; 1.3 cm point, this paper. Models: the solid curve is the model described in the Appendix for maximum luminosity, the dotted line is for minimum light, when the stellar luminosity is 2.5 times weaker and the surface temperature is 1700 K. The dash-dots, which overshoot the near IR data points, are flux densities from the star alone. The dashed line gives only the stellar flux, after extinction by the envelope of $A_{\rm V}= 48$ mag.

In the text

$\begin{figure} \par\includegraphics[width=7cm,clip]{4463fig4.eps} \end{figure}$ Figure A.2: Normalized model flux density as a function of aperture at five wavelengths. The star has an assumed angular diameter of 0 $\hbox{$.\!\!^{\prime\prime}$ }$ 075; at a comparable resolution essentially all the emission comes from the star. Substantial dust emission is indicated for beam sizes >1'' at IR wavelengths.

In the text