\begin{table}%t6
\caption{\label{Collapse scenario model parameters}Collapse scenario model parameters.}
%%\centering

\par
\begin{tabular}{llllll} 
\hline\hline\noalign{\smallskip}
& Initial number      & Parameter           & Minimum            & Plateau \\
 & density (cm$^{-3}$)  &                     & Temperature        & Point   \\
\hline\noalign{\smallskip}
Model 1               & 100                 & Time (yrs)          & $4.36 \times 10^6$  & $4.39 \times 10^6$  \\ 
Free-fall             & Atomic              & $n$ (cm$^{-3}$)      & $6.97 \times 10^5$  & $1.00 \times 10^8$   \\ 
%\hline
Model 2               & 1,000               & Time (yrs)          & $1.36 \times 10^6$  & $1.39 \times 10^6$  \\ 
Free-fall             & Atomic              & $n$ (cm$^{-3}$)      & $6.78 \times 10^5$  & $1.00 \times 10^8$   \\ 
%\hline
Model 3               & 10~000              & Time (yrs)          & $4.18 \times 10^5$  & $4.38 \times 10^5$  \\ 
Free-fall             & Atomic              & $n$ (cm$^{-3}$)      & $9.47 \times 10^5$  & $1.00 \times 10^8$   \\ 
%\hline
Model 4               & 100                 & Time (yrs)          & $2.18 \times 10^7$  & $2.19 \times 10^7$  \\ 
Retarded ($\times$ 5) & Atomic              & $n$ (cm$^{-3}$)      & $1.00 \times 10^6$  & $1.00 \times 10^8$   \\  
%\hline
Model 5               & 1000               & Time (yrs)          & $6.84 \times 10^6$  & $6.93 \times 10^6$  \\ 
Retarded ($\times$ 5) & Atomic              & $n$ (cm$^{-3}$)      & $9.87 \times 10^5$  & $1.00  \times 10^8$  \\ 
%\hline
Model 6               & 10~000              & Time (yrs)          & $2.07 \times 10^6$  & $2.19 \times 10^6$   \\ 
Retarded ($\times$ 5) & Atomic              & $n$(cm$^{-3}$)       & $7.73 \times 10^5$  & $1.00 \times 10^8$   \\ 
%\hline
Model 7               & 10~000              & Time (yrs)          & $4.18 \times 10^5$  & $4.38 \times 10^5$  \\ 
Free-fall             & Molecular           & $n$ (cm$^{-3}$)      & $9.47 \times 10^5$  & $1.00 \times 10^8$   \\ 
%\hline
Model 8               & 10~000              & Time (yrs)          & $2.07 \times 10^6$  & $2.19 \times 10^6$  \\ 
Retarded ($\times$ 5) & Molecular           & $n$(cm$^{-3}$)       & $7.73 \times 10^5$  & $1.00 \times 10^8$   \\ 
\hline
\end{tabular}
\vspace*{-2.5mm}
\end{table}