\begin{table}%t1
%\centering
\par
\caption{Astrophysical parameters of \hd. \vrad\ is measured in
the heliocentric rest frame.\label{astr_param}}
\begin{tabular}{lcccc}
\hline
\hline
Spectral Type                &    & B2.5            &    & (3)  \\
\teff\ (K)                   &    & $20~000\pm1000$ &    & (1)  \\
\logg\                       &    & 4.0             &    & (1)  \\
Log$L_{\ast}$ ($L_{\odot}$) &    & 2.83            &    & (1)  \\
$R_{\ast}$ (\rsol)           &    & 2.16            &    & (1)  \\
$M_{\ast}$ (\msol)           &    & $\geq$5        &    & (2)  \\
\vsini\ (\kms)               &    & $110\pm10$      &    & (1)  \\
$A_{\rm v}$ ({m})                 &    & 0.80            &    & (3)  \\
Age (Myr)                    &    & $\geq$0.5      &    & (2)  \\
\vrad\ (\kms)                &    & +17             &    & (4)  \\
\hline
\end{tabular}
\begin{list}{}{}
\item (1) This work; (2) Dr. L. Testi (private communication); (3)~\citet{valenti00}; (4) \citet{FINK_JAN84}.
\end{list}
\end{table}