Astronomy & Astrophysics

All Figures

$\begin{figure} \par\hspace*{2mm} \begin{tabular}{rlrl} \textbf{(a)} & \hspace{... ...ce{-0.3in} \includegraphics[width=3.2in]{2073fg1b.ps} \end{tabular} \end{figure}$ Figure 1: The distribution of effective optical depth in a disk resulting from a source of same-sized particles located at r₀. The particles evolve into the inner disk due to P-R drag and mutual collisions (which are assumed to be destructive). The steady state solution depends on the parameter $\eta _0$ which is defined by the source parameters. A value of $\eta _0 = 1$ corresponds to the situation when the collisional lifetime of the source particles (if they suffered no P-R drag evolution) is equal to their P-R drag lifetime. a) shows the functional dependence of the distribution on $\eta _0$ ; b) shows the distribution resulting from a source of particles with $\beta =0.5$ located at 30 AU from a solar mass star, but with different dust production rates that result in different effective optical depths at the source.
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In the text

$\begin{figure} \par\includegraphics[width=10.8cm,clip]{2073fig2.ps} \end{figure}$ Figure 2: The spectral energy distribution of emission from dust around main sequence ( left) A0, ( middle) G0 and ( right) M 0 stars. The top, middle and bottom rows of figures show dust from planetesimal belts at 3, 30 and 300 AU respectively. The dotted, dashed and dash-dot lines correspond to dust belts with $\eta _0 = 0.01$ , 1 and 100 respectively, where this has been converted to an optical depth distribution assuming $\beta =0.5$ . In reality the dust may have $\beta < 0.5$ , so these fluxes should be considered as conservative upper limits to the emission from these disks, even more so because black body emission efficiencies were assumed, whereas typical dust grains have much lower efficiencies at these wavelengths. The fluxes are normalised to stars at a distance of 10 pc, but naturally scale with distance squared. The solid line shows the stellar photosphere.
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In the text

$\begin{figure} \par\includegraphics[width=6.9cm,clip]{2073fig3.ps} \end{figure}$ Figure 3: The value of $\eta _0$ for the disks of the 37 stars in the debris disk database with excess flux measurements at two wavelengths plotted against the effective temperature of the stars. The disk around the star HD98800 falls off the plot at $\eta _0 \approx 10^{5}$ .
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In the text

$\begin{figure} \par\includegraphics[width=6.9cm,clip]{2073fig3.ps} \end{figure}$	Figure 3: The value of $\eta _0$ for the disks of the 37 stars in the debris disk database with excess flux measurements at two wavelengths plotted against the effective temperature of the stars. The disk around the star HD98800 falls off the plot at $\eta _0 \approx 10^{5}$ .
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