\begin{table}%Ta1 \caption{\label{table-collision-rates}CN$^-$--H$_2$ collision rate coefficients ($10^{-10}$ cm$^3$ s$^{-1}$).} \small%\centering \par \begin{tabular}{cccccccc} \hline \hline\noalign{\smallskip} & \multicolumn{7}{c}{Temperature (K)} \\ \cline{2-8} Transition & 10 & 20 & 30 & 40 & 50 & 60 & 70 \\ \hline 1 $\to$ 0 & 3.33 & 3.06 & 2.88 & 2.72 & 2.59 & 2.48 & 2.39 \\ 2 $\to$ 0 & 0.81 & 0.65 & 0.59 & 0.55 & 0.54 & 0.53 & 0.53 \\ 2 $\to$ 1 & 4.81 & 4.50 & 4.25 & 4.05 & 3.88 & 3.74 & 3.62 \\ 3 $\to$ 0 & 0.67 & 0.64 & 0.61 & 0.59 & 0.57 & 0.56 & 0.52 \\ 3 $\to$ 1 & 1.32 & 1.18 & 1.07 & 1.00 & 0.96 & 0.93 & 0.92 \\ 3 $\to$ 2 & 4.81 & 4.62 & 4.39 & 4.19 & 4.03 & 3.88 & 3.77 \\ \hline \end{tabular} \tablefoot{The complete set of de-excitation rate coefficients of CN$^-$ by collisions with para-H$_2$ considered in this study is available at the {\footnotesize BASECOL} website \protect\url{http://basecol.obspm.fr/}} \end{table}