The photosphere of T Tauri stars.

The authors have calculated the absorption spectrum in the wavelength interval 4880 - 5025 Å for a set of models with T_eff = 4000K and log g = 3.5 and a chromospheric temperature rise. These models are considered as representative of the atmosphere of T Tauri stars. The position of the temperature minimum goes from 0.1 to 2 gr cm^-2 in the models. Populations are in LTE and the two level plus continuum approximation is used for the source function. The authors compare the calculated spectra with those observed in the program of rotational velocity determination by Vogel and Kuhi (1981).