\begin{table}%t6
 \caption{\label{tab_obs_CH}Column densities, radial velocities and $b$ parameters of
    CH and CH$^+$ for HD~97048 and AB~Aur.}
%\centerline
{
\begin{tabular}{lcccccccccccccccccc}
  \hline
  \hline\noalign{\smallskip}
  Star    &  log $N$(CH)   & log $N$(CH$^+$) &   \vrad      &  $b$      \\
          & (cm$^{-2}$)   & (cm$^{-2}$)   & (\kms)       & (\kms)      \\
  \hline
 HD~97048  & 13.1~$\pm$~0.4 & 12.2~$\pm$~0.3 & 14.5~$\pm$~0.2 & 1.5~$\pm$~0.4 \\
 AB Aur    & 12.3~$\pm$~1.4 & 13.1~$\pm$~0.1 & 15.0~$\pm$~0.1 & 1.8~$\pm$~0.3   \\
\hline
\end{tabular}}
\tablefoot{The radial velocities are in the heliocentric rest frame.}
\end{table}