Low-mass pre-main sequence stars - T Tauri stars - can be divided into classical and weak-line T Tauri stars. Classical T Tauri stars, which are still surrounded by accretion disks, show strong emission lines, optical variability, and/or an infrared excess. Weak-line T Tauri stars, which do not exhibit these characteristics and presumably have dispersed their circumstellar matter already, are more easily detected by their strong coronal X-ray emission.
Based on data from the German X-ray satellite ROSAT and optical spectroscopic follow-up observations, the young star group at the LSW in collaboration with the MPE, Garching, has identified hundreds of hitherto unknown weak-line T Tauri stars in the nearby star forming regions of Taurus, Lupus, Orion and Chamaeleon. A major result of these studies was that these stars are widely dispersed around the molecular clouds, contrary to the classical T Tauri stars, which are located close to the molecular clouds.
Current activities concentrate on photometry of these stars as well as on their rotational periods (by photometric monitoring), Lithium abundances, radial and rotational velocities (by high-resolution echelle spectroscopy). Additionally, the width of the spatial distribution is investigated by the study of narrow strips on the sky.
Current members of the group are J. Krautter, R. Wichmann and S. Melchert.
List of papers recently published or submitted:
More information on current work in this field can be found in the Star Formation Newsletter.