\begin{table}%t2 
\par
%\centering
\par
\caption{Physical parameters of BA09 obtained by BBL91 (with upper limit errors) and in this work. Our errors are formal fitting errors followed
by a more realistic estimate of possible systematic errors.} 
\begin{tabular}{lcc}                                         
\hline\hline 
  & BBL91  & This work  \\  
\hline 
$T_{\rm eff}$ (K)   & 32~500~$\pm$~6700 & 29~446~$\pm$~81~$\pm$~500 \\ 
$\log g$            & 6.00~$\pm$~0.69    & 5.33~$\pm$~0.02~$\pm$~0.10 \\ 
$\log n$(He)/$n$(H)  & $<$$-$2.00& $-$2.54~$\pm$~0.03~$\pm$~0.20 \\ 
\hline 
\end{tabular} 
\end{table}