\begin{table}%t2
\caption{\label{tab:ostars}The stars shown in Fig.~\ref{fig:ostars} and their derived properties, using rotating stellar tracks.}
%\centering
\par
\begin{tabular}{lccccccc}
\hline\hline \noalign{\smallskip}
Association & HD & Name & Spectral type & Mass (Spec) & Mass (current) & Mass (Initial) & Age\\ 
\hline
OB1b & 36486 &  $\delta$ Ori A & O9.5II & 17.1 & 21.1 & 21.4 & 5.6\\
OB1b & 37468 &  $\sigma$ Ori A & O9.5V & 15.9 & 19.5 & 19.6 & 3.8\\
OB1b & 37742 &  $\zeta$ Ori A & O9.7Ib & 20.3 & 30.9 & 34.3 & 5.5\\
OB1b & 37128 &  $\epsilon$ Ori A & B0Ia& 45.5 & 34.6 & 40.8 & 5.7\\
OB1c & 37043 &  $\iota$ Ori A & O9III & 19.7 & 26.2 & 27.3 & 5.2\\
OB1c & 38771 &  $\kappa$ Ori & B0.5Ia & 27.3 & 28.0 & 31.8 & 6.2\\
OB1d & 37022 &  $\theta^1$ Ori C & O7Vp & 44.8 & 34.7 & 35.5 & 1.8\\
OB1d & 37041 &  $\theta^2$ Ori A & O9V & 27.5 & 24.0 & 24.1 & 2.2\\
OB1d & 37020 &  $\theta^1$ Ori A & B0.5V & 12.8 & 16.1 & 16.2 & 2.4\\
OB1d & 37023 &  $\theta^1$ Ori D & B0.5V & 18.4 & 17.7 & 17.7 & 0.6\\
OB1d & 37042 &  $\theta^2$ Ori B &B0.5V & 9.5 & 13.4 & 13.4 & 0.0\\
$\lambda$Ori & 36861 &  $\lambda$ Ori A & O8III & 38.8 & 34.0 & 37.0 & 4.2\\
\hline
\end{tabular}
\tablefoot {Numbers from the Henry Draper catalogue, commonly used names, spectral types are given, together with their spectral mass, and the initial and current masses assuming rotating stellar models.}
\end{table}