Differential emission measure analysis and sources of EUV radiation of capella's binary

Abstract

Abstract New EUVE spectra of Capella, containing strong emission lines in the temperature range 105–107 K, allow us to analyse the structure of the corona and the transition region of active component of this binary. We solve the standard stationary problem of the propagation of the thermal conduction flux from coronal to chromospheric layers. A comparison of the EUVE observational values of the emission measure with those derived from this computation shows that the structure of the lower corona and the upper part of the transition region is caused by a process of propagation of thermal flux from the corona downwards. We hence obtain a temperature distribution with height. Other sources of UV radiation (from the quiet G6 giant, the region of interaction between the stellar wind and the corona) are briefly discussed.