A LAMOST view of T Tauri stars in the Orion OB1 stellar associations

We perform a spectroscopic analysis of T Tauri stars (TTS) observed with the wide-field multi-fiber spectrograph LAMOST in the northern and southern OB1 substellar associations located in the Orion Star-Forming Complex. Three main parameters were determined: kinematic, obtained with the GAIA-EDR3 catalog; spectroscopic, obtained with LAMOST data and the SPTCLASS program (Hernández et al. 2017); and mid-IR photometry, obtained with the 2MASS (Ks band) and WISE (W3 and W4 bands) catalogs. Based on kinematic membership and the presence of the Li I 6707 Å line in absorption, we report properties for 148 TTS identified in the north fields and 244 TTS identified in the south. We categorized the stars by accretor class using the criteria established by Briceño et al. (2019), identifying 2 and 7 Classical TTS, 130 and 223 Weak-line TTS, and 11 and 13 Classical/Weak-line TTS, for the north and south fields respectively. Based on the mid-IR excesses, we identified stars that could have protoplanetary disks. We estimate the evolutionary state of the disk population using color-color diagrams. We obtained masses and ages with the MassAge code (Hernández et al. in prep) using the evolutionary models of MIST (Dotter, 2016) and PARSEC (Marigo et al., 2017). Two populations of TTS were identified in the southern fields, distinguished by distance but with similar ages (~4.5 Myr). The ratio of accretors to stars with protoplanetary disks is consistent with previous studies of Fang et al. (2009) and Briceño et al. (2019). Finally, we report 22 new TTS in the southern fields that were not in previous catalogs of the region.