\begin{table}%t1
%\centering
\par
\caption{B2 V stellar parameters.\label{tabla1}} 
$$
\begin{array}{cccccc}   %{p{0.5\linewidth}l}
\hline \hline
\noalign{\smallskip}
R/R_{\odot} \; & M/M_{\odot} \; & L/L_{\odot}  \; & T_{\rm eff}/K\; &\Gamma\;& A\;\\
\noalign{\smallskip}
\hline
\noalign{\smallskip}
4.5\;&9.0\;&3553.\;&21~000.\;& 9.27\times 10^{-3} \;&1413.\;\\
\noalign{\smallskip}
\hline
\end{array}
$$
\end{table}