\begin{table}%T3
\caption{\label{tab:upperlimits}{\it RV}~differences and estimates of companion masses. 
$\Delta${\it RV}~gives half peak-to-peak differences of the observed {\it RV}s listed in 
Tables~\ref{tab:bds} and~\ref{tab:tts}.
For {\it RV}~constant objects in this survey (upper part of the table), $\Delta${\it RV}~
is an upper limit for the {\it RV}~semiamplitude of hypothetical companions missed due to {\it RV}~precision.
For them, the last column lists upper limits for the companion minimum mass $M_2 \sin i$
derived by assuming a semimajor axis of 0.1~AU and circular orbits.
For {\it RV}~variable objects ({\it lower part of table}), the recorded {\it RV}~differences are  
lower limits for the {\it RV}~amplitudes of hypothetical companions.
For them, the last column gives a lower limit for the companion minimum mass $M_2 \sin i$
for separations of 0.2~AU (Cha~H$\alpha$~8) and 0.4~AU (CHXR~74, Sz~23), resp. 
Primary masses are taken from Comer\'on et~al. (\cite{Comer1999}, \cite{Comer2000}). 
}
%\centering
\par
\begin{tabular}{lcc}
\hline
\hline
Object& $\Delta${\it RV}~ & $M_2 \sin i$ \\
& [km~s$^{-1}$] & [$M_{\rm Jup}$]\\
\hline
{\it RV}~constant: & & max. $M_2 \sin i$\\
\hline
Cha~H$\alpha$~1   & 0.24 & 0.6 \\
Cha~H$\alpha$~2   & 0.13 & 0.4 \\
Cha~H$\alpha$~3   & 0.20 & 0.6 \\
Cha~H$\alpha$~4   & 0.21 & 0.8 \\
Cha~H$\alpha$~5   & 0.03 & 0.1 \\
Cha~H$\alpha$~6   & 0.28 & 0.6 \\
Cha~H$\alpha$~7   & 0.58 & 1.1 \\
Cha~H$\alpha$~12  & 0.56 & 1.5 \\
B~34               & 0.07 & 0.3 \\ 
\hline
{\it RV}~variable: & & min. $M_2 \sin i$\\
\hline
Cha~H$\alpha$~8   & 1.37 & 6 \\
CHXR~74            & 1.59 & 15 \\
Sz~23              & 1.09 & 13\\
\hline
\end{tabular}
\end{table}