\begin{table}%t2
\caption{\label{ratios}Line flux ratios in TW~Hya (notation as in Fig.~\ref{fe17}).}
%\centerline
 {\begin{tabular}{llrllr}
\hline\hline
$\lambda\lambda$ & Flux ratio & av$^{a}$& $\lambda\lambda$ & Flux ratio& av$^{a}$\\
\hline
M2/3G & \mbox{$0.57~\pm~0.16$} & 0.9 & 3D/3F & \mbox{$1.42~\pm~0.46$}&0.6\\
3G/3F & \mbox{$2.43~\pm~0.76$} & 1.3 & 3G/3C & \mbox{$1.06~\pm~0.26$}&0.8\\
M2/3F & \mbox{$1.39~\pm~0.48$} & 1.2 & 3G/3D & \mbox{$1.71~\pm~0.43$}&2.1\\
3D/3C & \mbox{$0.62~\pm~0.16$} & 0.4 & 3F/3C & \mbox{$0.43~\pm~0.19$}& 0.6\\
O($\beta/\alpha$) & \mbox{$0.18~\pm~0.03$} & 0.14 &Ne($\beta/\alpha$)& \mbox{$0.13~\pm~0.02$}&0.14\\
\hline
\end{tabular}}
\par
\smallskip
$^{a}$ Error-weighted average of stellar measurements.
\end{table}