The kinematics of T Tauri stars in the nearby star forming regions
Taurus-Auriga, Chamaeleon, Lupus and Scorpius-Centaurus is studied
using proper motions from the Hipparcos, PPM, ACT, TRC and STARNET
proper motion catalogues. Especially the STARNET catalogue is very
well suited for this purpose as it provides accurate proper motions
for about 4.3 million stars, so that a large number of T Tauri stars
is included in that catalogue. Where available, Hipparcos parallaxes
and radial velocities are combined with the proper motions to
calculate space velocities and velocity dispersions. In the
Scorpius-Centaurus association, the favourable geometry allows for the
determination of kinematical distances.
A large fraction of the stars in the samples belongs to the population of weak-line T Tauri stars discovered with the help of the X-ray satellite ROSAT during the last years. In contrast to classical T Tauri stars, which had preferentially been found very close to the densest cores of the cloud material in those star forming regions, weak-line T Tauri stars are distributed over larger regions in space. The kinematic signatures of processes producing such halos of weak-line T Tauri stars should still be visible, and the observed motions of the stars are analyzed in the framework of various star formation scenarios.
[ps-file] (4.4 MB)