HR diagram of the TWA stars listed in Table 5 with the grid of evolutionary models computed by Siess et al. (2000) with metallicity Z = 0.02(upper panel) and Baraffe et al. (1998) with Y = 0.282 and mixing length parameter of 1.9 (lower panel). The solid and dashed lines are, respectively, evolutionary tracks from 0.1 M_⊙ to 1 M_⊙ with mass increment of 0.1 M_⊙ and theoretical isochrones with the ages indicated in the figure. The green line indicates the zero-age main sequence (ZAMS) with the Siess et al. (2000) models, and the 1 Gyr isochrone computed by Baraffe et al. (1998). We assume a ± 100 K uncertainty for all spectral types.