\begin{table}%t7
\caption{Surface densities of different dust species at instant of Solar 
System formation and at the present time as predicted by the model calculation.}\label{TabSigDu}
%\centering
\small
\begin{tabular}{llcc}
\hline
\hline
%&&& \\[-8pt]
Dust species & Source & $\Sigma_{j{\rm ,d}}(t_{{\rm SSF}}) [M_{\odot}~{\rm pc^{-2}]}$ 
& $\Sigma_{j{\rm,d}}(t_{\rm G}) [M_{\odot}~{\rm pc^{-2}]}$\\
\hline
%&&& \\[-8pt]
	\multirow{3}{*}{Silicates}
&AGB 	& $5.39 \times 10^{-5}$ & $1.12 \times 10^{-4}$ \\
&SN II 	& $2.51 \times 10^{-6}$ & $2.08 \times 10^{-6}$ \\
&ISM 	& $2.76 \times 10^{-2}$ & $2.76 \times 10^{-2}$ \\
\hline
%&&& \\[-8pt]
	\multirow{3}{*}{Carbon}
&AGB	& $7.73 \times 10^{-4}$ & $5.73 \times 10^{-4}$ \\
&SN II	& $7.86 \times 10^{-5}$ & $7.73 \times 10^{-5}$ \\
&ISM 	& $1.43 \times 10^{-2}$ & $1.54 \times 10^{-2}$ \\
\hline
%&&& \\[-8pt]
	\multirow{4}{*}{Iron}
&AGB	& $1.89 \times 10^{-5}$ & $2.75 \times 10^{-5}$ \\
&SN II	& $7.72 \times 10^{-7}$ & $6.63 \times 10^{-7}$ \\
&SN Ia	& $9.83 \times 10^{-7}$ & $9.55 \times 10^{-7}$ \\
&ISM 	& $5.31 \times 10^{-3}$ & $6.78 \times 10^{-3}$ \\
\hline
%&&& \\[-8pt]
	\multirow{2}{*}{SiC}
&AGB	& $3.80 \times 10^{-5}$ & $4.58 \times 10^{-5}$ \\
&SN II	& $8.21 \times 10^{-7}$ & $6.82 \times 10^{-7}$ \\
\hline
\end{tabular}
\end{table}