Ultraviolet emission lines of T Tauri stars

Abstract

We present a study of the UV emission lines fluxes of the T Tauri stars (TTS). We have used for this purpose the final IUE sample of TTS which includes 33 TTS with good spectra in whole IUE range. We have derived the lines fluxes and compared them with the X-rays fluxes measured by the EINSTEIN satellite. Flux-flux diagrams are shown confirming that the X-rays flux of the TTSs is significantly lower than the expected if their atmospheres were similar to those of late-type main sequence stars. We have also found a weak correlation between the MgII and CIV lines fluxes suggesting that there is connection between the mechanism for line formation.