\begin{table}%T2
\caption{\label{lines}Observed emission lines.} 
\small%\centering
\par
\begin{tabular}{lcc}
\hline\hline
Line & Frequency [GHz]& {\it HPBW} [$''$]  \\ 
\hline
N$_2$D$^+$ 1--0 & 77.109 & 32 \\
N$_2$H$^+$ 1--0 & 93.173 & 27 \\
C$^{18}$O 1--0 & 109.782 & 22 \\
N$_2$D$^+$ 2--1 & 154.217 & 16 \\
N$_2$D$^+$ 3--2 & 231.322 & 11\\
HCO$^+$ 3--2 & 267.558 & 10 \\
\hline
\end{tabular}
\end{table}