A SEARCH FOR VERY-LOW MASS PRE-MAIN-SEQUENCE STARS IN TAURUS

We present the initial results of a deep CCD survey for very low mass pre-main-sequence (PMS) stars in selected fields of the Taurus molecul ar cloud complex. The results reported herein span a little over half a square degree in the dark clouds L1495, L1529, L1551, and B209. Our survey is complete down to I-C similar to 19 at (R-I)(C) similar to 2. 5, which enables us to probe well below the hydrogen burning limit at 1-2 Myr. From follow-up spectroscopic observations we have identified nine new low-mass T Tauri stars (TTSs). A large fraction of the new PM S objects (5/9) have very low masses as inferred from their late spect ral types (greater than or equal to M5), and comparison with recent ev olutionary tracks and Pleiades brown dwarfs suggests that our M6-M6.5 new TTSs are very young brown dwarfs. Two of the new TTSs may constitu te a new, moderately embedded, binary classical T Tauri system. The ne w young stars represent a similar to 38% increase in the known PMS pop ulation of our survey area and a factor of similar to 2 increase in th e number of known late-type TTSs. In spite of our sensitivity, we dete ct no young stars with spectral types later than similar to M7. Our re sults illustrate the importance of spectroscopy in eliminating foregro und M stars.