Chromospheric activity of ROSAT discovered weak-line T Tauri stars

We have started a high resolution optical observation program dedicated to the study of chromospheric activity in weak-lined T Tauri stars (WTTS) recently discovered by the ROSAT All-Sky Survey (RASS). It is our intention to quantify the phenomenology of the chromospheric activity of each star determining stellar surface fluxes in the more important chromospheric activity indicators, as well as to obtain the Li I abundance a better determination of the stellar parameters, spectral type, and possible binarity. In this contribution we present preliminary results from high resolution echelle spectroscopic observations at the 2.1m telescope of the McDonald Observatory. We have analysed, using the spectral subtraction technique, the Her and Ca II IRT lines of six WTTS located in and around the Taurus-Auriga molecular clouds.