\begin{table}%t2
\caption{\label{lines}Lines used for Doppler imaging of a~Cen and the approximate range of elemental abundances
over the surface of the star.}
%\centerline
{\small
 \begin{tabular}{cccrcc}
  \hline  \hline\noalign{\smallskip}
 Wavelength & Ion & E.P. & $\log{gf}$ & Min & Max \\
 (\AA)  & & (eV) &  & $\log{N/N_{\rm H}}$ & $\log{N/N_{\rm H}}$ \\
   \hline   
  4437.551 & He I & 21.242 & $-2.034$ & $-3.9$ & $-0.2$ \\
  6678.154 & He I & 21.242 & 0.329 \\
  7281.349 & He I & 21.242 & $-0.842$ \\
  4432.736 & N II   & 23.415 &  0.580 & $-4.9$ & $-2.9$ \\
  4447.030 & N II   & 20.409 &  0.285  \\
  6610.562 & N II   & 21.600 &  0.433  \\
  4414.900 & O II   & 23.442 &  0.172 & $-4.3$ & $-1.4$ \\
  4416.980 & O II   & 23.419 & $-0.077$  \\
  4419.596 & Fe III &  8.241 & $-2.218$ & $-5.8$ & $-2.0$ \\
  4431.019 & Fe III &  8.248 & $-2.572$  \\
  \hline
 \end{tabular}}\vspace*{2mm}
\end{table}