Newly discovered candidate weak-line T Tauri stars in the surrounding area of the Taurus-Auriga region

We present results of an extensive search for weak-line T Tauri stars (WTTS) in the outskirts of the Taurus-Auriga molecular cloud on the basis of the ROSAT All-Sky Survey Bright Source Catalog. Our surveyed region extends from 2(h)40(m) to 5(h)40(m) in right ascension and from 10 degrees to 40 degrees in declination. with the central part of Taurus-Auriga (4(h) < alpha < 5(h), 15 degrees < delta < 34 degrees), accomplished by Wichmann et al. (1996), excluded. Within a sky coverage of about 10(3) square degrees, 219 X-ray sources fulfil the criteria for selecting program sources suggested by Neuhauser et al. (1995a), and 164 of these X-ray sources were found to have at least one optical counterpart with E magnitude brighter than 16. Low-resolution spectroscopic observation has been carried out in order to discard early type stars and galaxies from the sample, additional intermediate-resolution spectra of a sub-sample of 156 late type optical counterparts were obtained for spectral classification and for the calculation of the equivalent width of H-alpha emission and LiI line absorption at 6707 Angstrom. Excluding 2 previously identified WTTS; a total of 75 new candidate WTTS and one possible classical T Tauri star have been discovered in our study. The majority of the newly found Li-rich optical counterparts are believed to be PMS stars rather than ZAMS stars as those of the Pleiades.