Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F1.eps} \end{figure}$ Figure 1: Geographic overview of the VLTI telescope stations on top of Cerro Paranal. Highlighted are the three baselines which have been used for the reported observations.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F2.eps} \end{figure}$ Figure 2: Summary of the visibility measurements on $\tau$ Cet with the E0-G1 and B3-M0 siderostats baselines. The UD model fit leads to $\theta _{\rm UD} = 2.032\pm 0.014 \pm 0.028$ mas.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F3.eps} \end{figure}$ Figure 3: Enlargement of Fig. 2 showing the high spatial frequency points obtained with the B3-M0 140 m baseline (siderostats).
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F4.eps} \end{figure}$ Figure 4: Summary of the visibility measurements on $\epsilon$ Eri with the three baselines in the K band and the associated best UD model fit: $\theta_{\rm UD} = 2.093~\pm 0.010 \pm 0.027$ mas.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F5.eps} \end{figure}$ Figure 5: Enlargement of Fig. 4 presenting the best UD model fit with its total (statistic and systematic) uncertainty in the high spatial frequency domain.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F6.eps} \end{figure}$ Figure 6: Overview of the visibilities measured on $\beta$ Leo with the B3-M0 140 m long baseline in Spring 2003 and best UD model fit with its 1 $\sigma$ (total) error: $\theta _{\rm UD} = 1.429 \pm 0.014 \pm 0.023$ mas.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{0189-F7.eps} \end{figure}$ Figure 7: Measured visibility amplitude for $\beta$ Pic with the UT1-UT3 102.5 m baseline in November 2001 and best UD model fit (solid) with its 1 $\sigma$ error (dashed): $\theta _{\rm UD} = 0.84 \pm 0.06 \pm 0.10$ mas.
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In the text

$\begin{figure} \par\includegraphics[width=4.2cm]{0189-F8.eps}\includegraphics[width=4cm]{0189-F9.eps} \end{figure}$ Figure 8: UV plane coverage (North is up and East to the right) for $\alpha$ PsA observations and comparison with the orientation of the disk resolved in the sub-mm (adapted from Holland et al. 2003). Its major axis is colinear to the short E0-G1 baseline (triangles for the K band, crosses for the H band) and perpendicular to UT1-UT3 (diamonds) and B3-M0 (circles) . The region probed by our interferometric observations is smaller than the SCUBA beam at 450 $\mu$ m.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F10.eps} \end{figure}$ Figure 9: Overview of the azimuth averaged K band visibilities obtained on three baselines for $\alpha$ PsA. The best UD model fit is superimposed (solid line): $\theta _{\rm UD} = 2.197 \pm 0.011 \pm 0.020$ mas. The low spatial frequency measurements do not contribute much to the global fit due to their larger uncertainty.
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In the text

$\begin{figure} \includegraphics[width=8.8cm,clip]{0189-F11.eps}\vspace*{4mm} \in... ....eps}\vspace*{4mm} \includegraphics[width=8.8cm,clip]{0189-F13.eps} \end{figure}$ Figure 10: Same data as in Fig. 9, but assumed to be representative of a non axisymetric brightness distribution. Best UD model fits for the perpendicular measurements are compared in the upper panel: $\theta _{\rm UD} = 2.191 \pm 0.011 \pm 0.018$ mas (solid) and $\theta _{\rm UD} = 2.289 \pm 0.042 \pm 0.046$ mas (dash-dotted). Enlargement of the fits and related data are shown in the middle and lower panels, with their associated error (dashed).
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F14.eps} \end{figure}$ Figure 11: H band visibility measurements of $\alpha$ PsA with the E0-G1 baseline in July 2002 during the IONIC experiment. Despite the larger uncertainty on the transfer function estimate and on the visibility points, the data are consistent and the best UD model fit gives: $\theta _{\rm UD} = 2.199 \pm 0.055 \pm 0.045$ mas, in good agreement with the K band measurement.
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F15.eps} \end{figure}$ Figure 12: Position of $\tau$ Ceti in the HR diagram (rectangle = spectrophotometry, parallelograms are the VINCI error domains). The filled diamond corresponds to a model with $M=0.83~M_{\odot}$ , $Z_{\rm i}=0.0145$ , the open circle to $M=0.81~M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F16.eps} \end{figure}$ Figure 13: Position of $\beta$ Leonis in the HR diagram. The filled diamond corresponds to $M=2.0~M_{\odot}$ , $Z_{\rm i}=0.042$ , the open circle to $M=2.03~M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F17.eps} \end{figure}$ Figure 14: Position of $\epsilon$ Eridani in the HR diagram. The filled diamond corresponds to $M=0.84~M_{\odot}$ , $Z_{\rm i}=0.0215$ , the open diamond to $M=0.83~M_{\odot}$ , $Z_{\rm i}=0.0215$ and the open circle to $M=0.83~M_{\odot}$ , $Z_{\rm i}=0.02$ .
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F18.eps} \end{figure}$ Figure 15: Position of $\beta$ Pictoris in the HR diagram. The filled diamond corresponds to $M=1.75~M_{\odot}$ , $Z_{\rm i}=0.0290$ , the open circle to $M=1.77~M_{\odot}$ . Due to the large uncertainty, only the 1 $\sigma$ error box is displayed.
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F19.eps} \end{figure}$ Figure 16: Position of $\alpha$ PsA in the HR diagram. The filled diamond corresponds to $M=2.00~M_{\odot}$ , $Z_{\rm i}=0.031$ , the open circle to $M=2.02~M_{\odot}$ .
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0189-F20.eps} \end{figure}$ Figure 17: Simulated visibility profiles for a 2 mas UD diameter star with no environment (solid line) or surrounded by a faint and narrow uniform ring ( $F^{\rm ring}=0.02 F^{\rm tot}$ ) located at 40 stellar radii (dashed line). The departure from the Airy function reaches about 5 $\%$ at very low spatial frequency whereas the curve can be approximated in the high frequency domain by the Airy function of a slightly bigger star.
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In the text

$\begin{figure} \par\includegraphics[width=8.7cm,clip]{0189-F21.eps}\par\includegraphics[width=8.7cm,clip]{0189-F22.eps} \end{figure}$ Figure 18: Oblateness of $\beta$ Pic ( $R_{\rm Pole} = 1.53$ $R_{\odot }$ , $v\sin i = 130$ km s^-1) and $\alpha$ PsA ( $R_{\rm Pole} =1.83~ R_{\odot}$ , $v\sin i = 93$ km s^-1). Predicted V² difference between measurements along the polar and equatorial directions for various inclinations (z) of the rotation axis. The influence of the gravity-darkening (VZ) is also shown in the case of $\beta$ Pic. The arrows indicate the spatial frequency of our interferometric measurements.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0189-F23.eps} \end{figure}$ Figure 19: Maximum dust/stellar flux ratio derived from the visibility measurements at different spatial frequencies, after correction of the expected oblateness for the fast rotating stars. The constraint on the presence of hot dust in a ring is only slightly weaker than that inferred from spectroscopic measurements.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F1.eps} \end{figure}$	Figure 1: Geographic overview of the VLTI telescope stations on top of Cerro Paranal. Highlighted are the three baselines which have been used for the reported observations.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F2.eps} \end{figure}$	Figure 2: Summary of the visibility measurements on $\tau$ Cet with the E0-G1 and B3-M0 siderostats baselines. The UD model fit leads to $\theta _{\rm UD} = 2.032\pm 0.014 \pm 0.028$ mas.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F3.eps} \end{figure}$	Figure 3: Enlargement of Fig. 2 showing the high spatial frequency points obtained with the B3-M0 140 m baseline (siderostats).
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F4.eps} \end{figure}$	Figure 4: Summary of the visibility measurements on $\epsilon$ Eri with the three baselines in the K band and the associated best UD model fit: $\theta_{\rm UD} = 2.093~\pm 0.010 \pm 0.027$ mas.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F5.eps} \end{figure}$	Figure 5: Enlargement of Fig. 4 presenting the best UD model fit with its total (statistic and systematic) uncertainty in the high spatial frequency domain.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F6.eps} \end{figure}$	Figure 6: Overview of the visibilities measured on $\beta$ Leo with the B3-M0 140 m long baseline in Spring 2003 and best UD model fit with its 1 $\sigma$ (total) error: $\theta _{\rm UD} = 1.429 \pm 0.014 \pm 0.023$ mas.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{0189-F7.eps} \end{figure}$	Figure 7: Measured visibility amplitude for $\beta$ Pic with the UT1-UT3 102.5 m baseline in November 2001 and best UD model fit (solid) with its 1 $\sigma$ error (dashed): $\theta _{\rm UD} = 0.84 \pm 0.06 \pm 0.10$ mas.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F10.eps} \end{figure}$	Figure 9: Overview of the azimuth averaged K band visibilities obtained on three baselines for $\alpha$ PsA. The best UD model fit is superimposed (solid line): $\theta _{\rm UD} = 2.197 \pm 0.011 \pm 0.020$ mas. The low spatial frequency measurements do not contribute much to the global fit due to their larger uncertainty.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0189-F14.eps} \end{figure}$	Figure 11: H band visibility measurements of $\alpha$ PsA with the E0-G1 baseline in July 2002 during the IONIC experiment. Despite the larger uncertainty on the transfer function estimate and on the visibility points, the data are consistent and the best UD model fit gives: $\theta _{\rm UD} = 2.199 \pm 0.055 \pm 0.045$ mas, in good agreement with the K band measurement.
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F15.eps} \end{figure}$	Figure 12: Position of $\tau$ Ceti in the HR diagram (rectangle = spectrophotometry, parallelograms are the VINCI error domains). The filled diamond corresponds to a model with $M=0.83~M_{\odot}$ , $Z_{\rm i}=0.0145$ , the open circle to $M=0.81~M_{\odot}$ .
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F16.eps} \end{figure}$	Figure 13: Position of $\beta$ Leonis in the HR diagram. The filled diamond corresponds to $M=2.0~M_{\odot}$ , $Z_{\rm i}=0.042$ , the open circle to $M=2.03~M_{\odot}$ .
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F17.eps} \end{figure}$	Figure 14: Position of $\epsilon$ Eridani in the HR diagram. The filled diamond corresponds to $M=0.84~M_{\odot}$ , $Z_{\rm i}=0.0215$ , the open diamond to $M=0.83~M_{\odot}$ , $Z_{\rm i}=0.0215$ and the open circle to $M=0.83~M_{\odot}$ , $Z_{\rm i}=0.02$ .
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F18.eps} \end{figure}$	Figure 15: Position of $\beta$ Pictoris in the HR diagram. The filled diamond corresponds to $M=1.75~M_{\odot}$ , $Z_{\rm i}=0.0290$ , the open circle to $M=1.77~M_{\odot}$ . Due to the large uncertainty, only the 1 $\sigma$ error box is displayed.
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0189-F19.eps} \end{figure}$	Figure 16: Position of $\alpha$ PsA in the HR diagram. The filled diamond corresponds to $M=2.00~M_{\odot}$ , $Z_{\rm i}=0.031$ , the open circle to $M=2.02~M_{\odot}$ .
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0189-F23.eps} \end{figure}$	Figure 19: Maximum dust/stellar flux ratio derived from the visibility measurements at different spatial frequencies, after correction of the expected oblateness for the fast rotating stars. The constraint on the presence of hot dust in a ring is only slightly weaker than that inferred from spectroscopic measurements.
Open with DEXTER