Structure of the shock at the surface of CTTS

A steady-state structure and spectrum of the accretion zone at the surface of T Tauri stars are numerically simulated. This modeling uses well-developed methods of the theory of stellar atmospheres with inclusion of the effects of the gas motion (advection and the doppler shift of the lines). The spectrum $I_{\nu}(\mu)$ and cooling rate of shocked gas are calculated. It is found that at the pre-shock densities $N_0>10^{13}$ cm$^{-3}$ helium and hydrogen lines show a red-shifted absorption, significantly broadened by the Stark effect.