  We investigate the evolution of circumstellar discs around T Tauri stars that
are ejected from small stellar clusters within molecular clouds. In particular,
we study how the interaction that leads to ejection may hasten the transition
between Classical and Weak-lined T Tauri status. In our models, ejections of T
Tauri stars at velocities of 3-10 km/s truncate the accretion disc at radii
between 1 and 10 a.u., reducing the viscous evolution time of the disc so that
accretion rapidly ceases. The observational appearance of the resulting systems
is then dependent on the presence or absence of a stellar magnetic field. For
non-magnetic stars we find that a near-infra red excess should persist due to
reprocessing of stellar radiation, but that this is greatly diminished for
magnetic T Tauri stars by the presence of a magnetosphere extending to
corotation. In either case, there is a period when ejected stars should appear
as non-accreting systems with detectable circumstellar material at wavelengths
of 5 microns and beyond. We discuss the implications of these results for
models in which ejected stars contribute to the halo of pre-main-sequence
objects discovered from ROSAT observations of star forming regions and the
All-Sky Survey.
