\begin{table}%t6
\caption{\label{tab_pm3}Proper motions of known T dwarfs in mas/yr.}
%\centering
\par
\begin{tabular}{@{\extracolsep{-5pt}}llrrr}
\hline\hline\noalign{\smallskip}
Object & SpT (Ref) & $\mu_{\alpha}\cos{\delta}$ & $\mu_{\delta}$ & $\varepsilon$ \\
\hline
SDSS~J0325$+$04     & T5.5 (1) &  $-$185 $\pm$ 06 &   $+$15 $\pm$ 07 & 27 \\
2MASSI~J0755$+$22   & T5.0 (2) &   $-$13 $\pm$ 03 &  $-$241 $\pm$ 05 & 11 \\
SDSS~J0830$+$01     & T4.5 (2) &  $+$214 $\pm$ 06 &  $-$329 $\pm$ 09 & 08 \\
2MASS~J1231$+$08    & T5.5 (2) & $-$1185 $\pm$ 09 & $-$1050 $\pm$ 12 & 14 \\
SDSS~J1504$+$10     & T7.0 (1) &  $+$338 $\pm$ 13 &  $-$350 $\pm$ 11 & 21 \\
2MASSI~J2339$+$13   & T5.0 (2) &  $+$380 $\pm$ 05 &  $-$971 $\pm$ 05 & 12 \\
\hline
\end{tabular}
\tablefoot{Proper motions as obtained from linear fitting of 
UKIDSS, SDSS, and
(if available) 2MASS and DENIS positions. 
$\varepsilon$ are the expected errors (see text).
For full names
and references, see Gelino et~al. (\cite{gelino09}).
Spectral type (SpT) references (Ref):
(1) - Chiu et~al. (\cite{chiu06});
(2) - Burgasser et~al. (\cite{burgasser06b}).}
\end{table}