The chromosphere and corona of T Tauri

Observations of the ultraviolet spectrum of the pre-main-sequence star T Tauri have been made using the International Ultraviolet Explorer (IUE) satellite. The fluxes of the emission lines are used to make models of the temperature and density structure of the chromosphere and transition region to the corona. Several models are discussed to cover the range of possible gas and electron pressures. Various spectroscopic techniques are used to limit the range of acceptable electron pressures. Previous observations in the X-ray flux measured with the Einstein satellite by previous authors are used to extend the model to a corona at Tsub(e) approx. 5 x 106 K. It is difficult to avoid the conclusion that a two-component atmosphere is required. (author)