\begin{table}%t3
%\centering
\par
\caption{\label{cs param}Main spectroscopic parameters of the studied lines.}
\small \begin{tabular}{l c c c  c} 
\hline \hline  
Species        & Transition     &  Frequency &  $A_{\rm ij}$  & $E_\emr{upp}$ \\
&  $J_\emr{upp}{-}J_\emr{low}$   &    (GHz)   & (s$^{-1}$)           &     (K)      \\
\hline\noalign{\smallskip}
HCO$^+$        & 1--0           &  89.188523 & $4.2\times10^{-5}$ &  4.3	  \\ 
HOC$^+$        & 1--0           &  89.487414 & $2.2\times10^{-5}$ &  4.3	  \\ 
\HthCOp{}      & 1--0           &  86.754288 & $3.9\times10^{-5}$ &  4.2	  \\
CO$^+$         & 2(5/2)--1(3/2) & 236.062578 & $4.7\times10^{-4}$ &  17.2	  \\
\HthCOp{}      & 3--2           & 260.255339 & $1.3\times10^{-3}$ &  25.0	  \\
DCO$^+$        & 2--1           & 144.077289 & $2.1\times10^{-4}$ &  10.4	  \\ 
DCO$^+$        & 3--2           & 216.112582 & $7.7\times10^{-4}$ &  20.7	  \\ 
\hline
\end{tabular}
\end{table}