\begin{table}%t1
%\centering
\par
\caption{Composition of different types of ash. The ashes of type
M1, M2, and M3 are chosen to resemble NSE for  $\rho = \unit[3.2
\times 10^{7}]{g\ cm^{-3}}$, $\rho = \unit[5.0 \times 10^{7}]{g\
  cm^{-3}}$, and $\rho = \unit[1.0 \times 10^{8}]{g\ cm^{-3}}$.
\label{tab:comp}}
\begin{tabular}{l*{5}{c}}
\hline\hline
Isotop  & N             & S             & M1                                    & M2                                    & M3                                    \\
\hline\\[-3mm]
He4             &               &               & $6.14\times 10^{-3}$   & 0,0153                                & 0.0537                                \\
C12             &               &               & $2.81\times 10^{-4}$   & $1.47\times 10^{-4}$   & $1.57\times10^{-4}$    \\
O16             &               &               & $3.87\times 10^{-3}$   & $8.49\times 10^{-4}$   & $6.23\times10^{-4}$    \\
Ne20    &               &               & $1.93\times 10^{-5}$   & $7.03\times 10^{-6}$   & $1.19\times 10^{-5}$   \\
Mg24    &               &               & $4.91\times 10^{-4}$   & $8.03\times 10^{-4}$   & $1.17\times 10^{-3}$   \\
Si28    &               & 1.0   & 0.417                                 & 0.388                                 & 0.277                                 \\
S32             &               &               & 0.311                                 & 0.281                                 & 0.212                                 \\
Ar36    &               &               & 0.114                                 & 0.105                                 & 0.0916                                \\
Ca40    &               &               & 0.103                                 & 0.0924                                & 0.0845                                \\
Ti44    &               &               & $1.11\times 10^{-3}$   & $1.34\times 10^{-3}$   & $2.16\times 10^{-3}$   \\
Cr48    &               &               & $1.83\times 10^{-3}$   & $3.04\times 10^{-3}$   & $7.01\times 10^{-3}$   \\
Fe52    &               &               & $6.41\times 10^{-3}$   & 0.0147                                & 0.0376                                \\
Ni56    & 1.0   &               & 0.0348487                     & 0.09741397                    & 0.2324681                     \\
\hline
\end{tabular}
\end{table}