\begin{table}%t3
\caption{The atmospheric parameters of $\alpha$~Cen~A and B
derived from various methods. The mean \Teffb is  weighted by the
inverse variances (see text).} \label{results}
\small%\centering
\par
\begin{tabular}{l c c c c c c c c }
\hline\hline
&\Teff(K)&\Teff(K)&\Teff(K)&\Teff(K)&$\log g$&$\log g$&\multirow{2}{*}{$\rm
[Fe/H]$}&\multirow{2}{*}{$\xi_t$(km~s$^{-1}$)}\\
                &excitation       & H$\alpha$~     & photometric   &
weighted mean  &ionization& direct&      &\\
\hline
{$\alpha$~Cen~A}&{5847} $\pm$ {27}&{5793} $\pm$ {50}   &
{5794} $\pm$ {34}
&{5824} $\pm$ {26}&{4.34} $\pm$ {0.12}&{4.307} $\pm$ {0.005}&$+${0.24} $\pm$ {0.03}&{1.46} $\pm$ {0.03}\\
{$\alpha$~Cen~B}&{5316} $\pm$ {28}&{5155} $\pm$ {100}  &
{5182} $\pm$ {19}
&{5223} $\pm$ {62}&{4.44} $\pm$ {0.15}&{4.538} $\pm$ {0.008}&$+${0.25} $\pm$ {0.04}&{1.28} $\pm$ {0.12}\\\hline
\end{tabular} 
\end{table}