\begin{table}%t2
%\centering
\par
\caption{\label{table_parameters}Parameters of single and two protostellar envelope (PE) models.}
\tiny \begin{tabular}{l|r|rr}        
\hline\hline \noalign{\smallskip}                
 Parameter  &  Single  PE &  PE 1 &  PE 2 \\    
\hline
Outer radius (AU)                 & 12~000              & 12~000                     & 12~000\\
Luminosity (\lsun)               &  10$^5$            & $5 \times 10^4$   &  $5 \times 10^4$  \\
Mass (\msun)                      &  250                   &  125                        &  125     \\
\agua                                   &  $2\times10^{-8}$  &  $1.8\times10^{-8}$  &  $8\times10^{-10}$      \\
Post-jump \agua                 &   $1\times10^{-4}$ &  $1\times10^{-4}$ &  $1\times10^{-4}$ \\
\vtur~(\kms)                      & 2.0                            &  0.4                          &  0.5                \\
\vexp~(\kms)                     & 2.0                            &  1.1                          &  1.2      \\
\vlsr ~(\kms)                      & --38                          &  --37.0                       &  --40.5           \\
\hline                                   
\end{tabular}\vspace{-4mm}
\end{table}