Forbidden line and H-alpha profiles in T Tauri star spectra - A probe of anisotropic mass outflows and circumstellar disks

The results of a high-resolution spectroscopic study of 10 T Tauri stars (TTS) and two Herbig emission stars are presented based on red echelle spectra including the lines of forbidden O I 6300 A, forbidden N II 6584 A, forbidden S II 6716, 6731 A, as well as H-alpha. The forbidden lines display a continuous progression of profile types. The velocity structure in the forbidden lines is critically examined and compared to computed line profiles for a number of different wind models. Constant velocity spherical or conical winds fail to reproduce the observed line profiles, which are better explained by a wind with a latitude-dependent velocity field. A prediction of the wind model correlating the velocity of the reversal at H-alpha and the forbidden line velocity structure as a function of the view angle to the star is explored. Estimates of the average densities and sizes for the TTS forbidden emission regions are presented, and mass-loss rates are computed. IRAS far-IR fluxes are used to estimate the disk sizes.