\begin{table}%t2
\caption{Best fit parameters.}\label{parameter}
\small%\centerline
{
\begin{tabular}{l c}
\hline \hline
Free parameter & Value \\
\hline 
Inclination of disc, $i$& 74$^\circ$ \\
Flatness of disc, $\sin^f(\theta)$ & 3.8 \\
Central mass, $M_*$ & 1.35 $M_\odot$ \\ 
Velocity angle, $\alpha$ & 15$^\circ$ \\
\\
Abundance of CO$^*$ & 	$3.5\times10^{-5}$\\
Abundance of CS&   		$0.5\times10^{-9}$\\
Abundance of SO &  		$2.0\times10^{-9}$\\
Abundance of HCO$^+$ & 	$1.9\times10^{-9}$\\
Abundance of HCN & 		$0.2\times10^{-9}$\\
Abundance of HNC & 		$0.2\times10^{-9}$\\
Abundance of CN &  		$0.2\times10^{-9}$\\
Abundance of H$_2$CO & 	$0.7\times10^{-9}$\\  
\hline
Fixed parameters & \\
\hline
Disc mass& 0.097 $M_\odot$\\
Temperature slope & $-0.35$\\
Temperature at 1000~AU & 19.42~K\\ 
Density slope & $-1.8$\\
Turbulent velocity, {\it FWHM} & 0.2 km s$^{-1}$\\
Outer radius & 2000 AU\\
Distance & 140 pc\\
\hline
\end{tabular}}
\medskip
$^*$ The main isotopic abundance has been derived from the C$^{18}$O~abundance using a~$^{16}$O/$^{18}$O~ratio of~540 \citep{wilson1994}.
\end{table}