2017MNRAS.468.3557B

In this work, we use the semi-empirical atmospheric modelling method to obtain the chromospheric temperature, pressure, density and magnetic field distribution versus height in the K2 primary component of the RS CVn binary system HR 7428. While temperature, pressure and density are the standard output of the semi-empirical modelling technique, the chromospheric magnetic field estimation versus height comes from considering the possibility of not imposing hydrostatic equilibrium in the semi-empirical computation. The stability of the best non-hydrostatic equilibrium model implies the presence of an additive (towards the centre of the star) pressure that decreases in strength from the base of the chromosphere towards the outer layers. Interpreting the additive pressure as magnetic pressure, we estimated a magnetic field intensity of about 500 G at the base of the chromosphere.