\begin{table}%t1
\caption{Observational properties of the stars analyzed in this paper. Spectral types are from \citet{pgm06}. Values of extinction are taken from \citet{schoedel07}. A~distance of 7.62~kpc is adopted \citep{frank05}.}\label{tab_obs}
%\centering
\small
\begin{tabular}{llrrrl}
\hline\hline
Star    & ST        & $m_{K}$  & $A_{K}$ & $M_{K}$  & Alternative name \\
\hline                					34W     &  Ofpe/WN9 & 12.5 $\pm$ 0.1 & 3.0  $\pm$  0.2 & --6.0 $\pm$ 0.3 & GCIRS 34W        \\
16NW    &  Ofpe/WN9 & 10.0 $\pm$ 0.1 & 2.3 $\pm$ 0.1 & --6.7 $\pm$ 0.2 & GCIRS 16NW       \\
16C     &  Ofpe/WN9 &  9.7 $\pm$ 0.1 & 2.3 $\pm$ 0.1 & --7.0 $\pm$ 0.2 & GCIRS 16C        \\ 
33E     &  Ofpe/WN9 & 10.1 $\pm$ 0.1 & 2.5 $\pm$ 0.1 & --6.8 $\pm$ 0.2 & GCIRS 33E        \\
AF      &  Ofpe/WN9 & 10.8 $\pm$ 0.1 & 2.2 $\pm$ 0.1 & --5.8 $\pm$ 0.2 & NAME AF STAR     \\ 
15NE    &  WN8      & 11.8 $\pm$ 0.1 & 2.0 $\pm$ 0.2 & --4.6 $\pm$ 0.3 & GCIRS15 NE       \\
AFNW    &  WN8      & 11.7 $\pm$ 0.1 & 2.3 $\pm$ 0.2 & --5.0 $\pm$ 0.3 & NAME AF NW       \\
9W      &  WN8      & 12.1 $\pm$ 0.1 & 2.7 $\pm$ 0.2 & --5.0 $\pm$ 0.3 & GCIRS 9W         \\
7E2     &  WN8      & 12.9 $\pm$ 0.1 & 2.6 $\pm$ 0.2 & --4.1 $\pm$ 0.3 & GCIRS 7E2        \\
13E2    &  WN8      & 10.8 $\pm$ 0.1 & 2.0 $\pm$ 0.3 & --6.4 $\pm$ 0.4 & GCIRS 13E2       \\
7SW     &  WN8/WC9  & 12.0 $\pm$ 0.1 & 2.8 $\pm$ 0.2 & --5.2 $\pm$ 0.3 & $-$              \\
15SW    &  WN8/WC9  & 12.0 $\pm$ 0.1 & 2.0 $\pm$ 0.2 & --4.4 $\pm$ 0.3 & GCIRS 15SW       \\
AFNWNW  &  WN7      & 12.6 $\pm$ 0.1 & 2.6 $\pm$ 0.2 & --4.4 $\pm$ 0.3 & $-$              \\
34NW    &  WN7      & 12.8 $\pm$ 0.1 & 3.0 $\pm$ 0.2 & --4.6 $\pm$ 0.3 & $-$              \\
16SE2   &  WN5/6    & 12.0 $\pm$ 0.1 & 2.6 $\pm$ 0.2 & --5.0 $\pm$ 0.3 & GCIRS 16SE2      \\
7W      &  WC9      & 13.1 $\pm$ 0.1 & 2.5 $\pm$ 0.2 & --3.8 $\pm$ 0.3 & GCIRS 7W         \\
7SE     &  WC9      & 13.0 $\pm$ 0.1 & 2.6 $\pm$ 0.2 & --4.0 $\pm$ 0.3 & GCIRS 7SE        \\
13E4    &  WC9      & 11.7 $\pm$ 0.1 & 2.8 $\pm$ 0.3 & --5.5 $\pm$ 0.4 & GCIRS 13E4       \\
\hline
\end{tabular}
\end{table}