\begin{table}%t2
\caption{Orion proplyds observational parameters: comparison with previous papers.
\label{table:2}}
%\centerline
{\begin{tabular}{@{} lccccrccrr @{}}
\hline\hline
\noalign{\smallskip}
Paper & \multicolumn{2}{c}{Total} & \multicolumn{2}{c}{Common} &\multicolumn{2}{c}{Max. $d_{\rm proj}\theta^{1}$ OriC} & $\langle R \rangle$ &  {$r_{\rm IF}$}&  {$r_{\rm disk}$}\\
\noalign{\smallskip}
& IF & disks & IF & disks & ($''$) & (pc)& (\%) & (\%) & (\%)  \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
B98a$^{{a}}$ & 40 & 21 & 34 & 19 & 70.0 & 0.15  (184--427) & $43\pm18$ & 30 &  14\\ 
O98$^{{b}}$ & 22 & -- & 20 & -- & 70.0 & 0.15 (184--427) & -- & 22 & -- \\
JHB98$^{{c}}$ & 41 & 15 & 30 & 15 & 70.0 & 0.15  (184--427) & $48\pm22$ & 42 & 7 \\
SH99$^{{d}}$ & 10 & 10 & 10 & 10 & 56.7  & 0.12  (182--413) & $48\pm20$ &  55 & 70\\
B00$^{{e}}$ & 24 & 24 &18 & 18 & 176.3 & 0.38 (072--135) & $44\pm17$ & 2 & 8 \\
\hline
\end{tabular}}
\par
\smallskip
$^{{a}}$ Bally et~al. (1998a);
$^{{b}}$ O'Dell (1998);
$^{{c}}$ Johnstone et~al. (1998);
$^{{d}}$ St\"orzer \& Hollenbach (1999);
$^{{e}}$ Bally et~al. (2000).\\
 This table refers only to the sample of bright proplyds listed in previous papers and deliberately excludes the pure silhouettes. The second column refers to the total number of bright proplyds (here IF) and bright proplyds with embedded disks (here disks) listed in the papers. The third column refers to the subsample of objects that are common to our sample. $\langle R\rangle$ is the diameter ratio computed for the common sample of embedded disks. The ma\-xi\-mum projected distances listed here are the ones measured in \textit{this} paper assuming 
 1~pix~$\sim$~0.$^{\prime\prime}$1~=~45~AU and $d_{\rm Orion}$~=~450~pc; the differences between the different papers were negligible. The linear correlation coefficients  {$r_{\rm IF}$} and  
 $r_{\rm disk}$  are represented by its square times~100\%. 
Bally et~al. (2000) makes reference to many other proplyds but, we just consider the 24~H$_\alpha$ emission bright proplyds with dark disks embedded.
\end{table}