\begin{table}%T2
\caption{Polarization results of stars in Pismis~20.}\label{tab2}
%\centerline
{
\begin{tabular}{lcccccc}
\noalign{\smallskip}
\hline \hline
\noalign{\smallskip}
Star$^{a}$ & $P_{\rm max}$  &  $\epsilon_{\rm p}$ & $\sigma_1^{b}$ &
		$\lambda_{\rm max}$ & $\epsilon_{\lambda}$ & Sp. T. \\
& \% & & & $\mu$m & &  \\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
1   &   5.96& 0.23& 1.91& 0.61&  0.06&  -- \\
2   &   6.18& 0.51& 1.78& 0.55&  0.09&  -- \\
3   &   3.51& 0.64& 0.84& 0.73&  0.21& B0 I-III \\
4*  &   1.81& 0.20& 0.97& 0.48&  0.07&  -- \\
7   &   3.98& 0.32& 1.45& 0.59&  0.07& O9.5 Ib \\
8   &   6.17& 0.12& 1.23& 0.57&  0.02& B2 Ia-O \\
9   &   4.80& 0.29& 1.11& 0.55&  0.04& B0.2 III \\
10  &   6.95& 0.28& 2.14& 0.58&  0.05&  -- \\
11  &   6.46& 0.11& 0.78& 0.56&  0.02& O9.5Ib \\
12  &   3.91& 0.37& 0.52& 0.48&  0.05&  -- \\
13  &   6.57& 0.16& 2.36& 0.57&  0.03& O9 Vn \\
Vz14* & 2.58& 0.13& 1.13& 0.67&  0.07&  -- \\
WR67  & 6.45& 0.21& 1.77& 0.56&  0.04& WN6 + OB? \\                                  
Vz30*  &   1.68& 0.13& 1.30& 0.57&  0.06&  -- \\
Vz107* &   1.99& 0.17& 1.50& 0.56&  0.09&  -- \\
Vz121  &   4.88& 0.18& 1.02& 0.69&  0.05&  -- \\
Vz128  &   4.06& 0.07& 0.51& 0.76&  0.03&  -- \\
Vz148  &   4.52& 0.65& 2.08& 0.70&  0.21&  -- \\
Vz182  &   5.71& 0.04& 0.63& 0.56&  0.01&  -- \\
Vz183* &   2.23& 0.25& 1.42& 0.69&  0.14&  -- \\
\hline
\end{tabular}}
\par
\smallskip
$ ^{a}$ Identifications from Lyng\aa~(1968) or from V\'azquez et~al. (1995;~Vz). * Stands for nonmember.\\
$ ^{b}$ $ {\sigma_{1}}^2  =  \sum {(r_{\lambda}/{\epsilon
_{\rm p_{\lambda}})^2}}/(m-2)$;  where   $m$ is the number of colors and $r_{\lambda} = P_{\lambda} - P_{\rm
max}~\exp(-K~{\ln}^2({\lambda_{\rm max}/{\lambda}))}$.
\end{table}