1998A&AS..132..173L

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^h40^m to 5^h40^m in right ascension and from 10° to 40° in declination, with the central part of Taurus-Auriga (4^h<α< 5^h, 15°<δ< 34°), accomplished by Wichmann et al. (1996A&A...312..439W), excluded. Within a sky coverage of about 10³ square degrees, 219 X-ray sources fulfil the criteria for selecting program sources suggested by Neuhaeuser et al. (1995A&A...295L...5N), 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_α emission and LiI line absorption at 6707Å. 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.