  Context. In multiple pre-main-sequence systems the lifetime of circumstellar
disks appears to be shorter than around single stars, and the actual
dissipation process may depend on the binary parameters of the systems. Aims.
We report high spatial resolution observations of multiple T Tauri systems at
optical and infrared wavelengths. We determine if the components are
gravitationally bound and orbital motion is visible, derive orbital parameters
and investigate possible correlations between the binary parameters and disk
states. Methods. We selected 18 T Tau multiple systems (16 binary and two
triple systems, yielding $16 + 2\times2=20$ binary pairs) in the Taurus-Auriga
star forming region from the survey by Leinert et al. (1993), with spectral
types from K1 to M5 and separations from 0.22" (31 AU) to 5.8" (814 AU). We
analysed data acquired in 2006-07 at Calar Alto using the AstraLux lucky
imaging system, along with data from SPHERE and NACO at the VLT, and from the
literature. Results. We found ten pairs to orbit each other, five pairs that
may show orbital motion and five likely common proper motion pairs. We found no
obvious correlation between the stellar parameters and binary configuration.
The 10 $\mu$m infra-red excess varies between 0.1 and 7.2 magnitudes (similar
to the distribution in single stars, where it is between 1.7 and 9.1), implying
that the presence of the binary star does not greatly influence the emission
from the inner disk. Conclusions. We have detected orbital motion in young T
Tauri systems over a timescale of $\approx20$ years. Further observations with
even longer temporal baseline will provide crucial information on the dynamics
of these young stellar systems.
