Model chromosphere and transition region for 56 Peg (K0 IIp + wd): A preliminary study

Observations of 56 Peg (K0 IIp + wd) have shown the presence of ultraviolet emission lines associated with warm (105 K) material. It has been suggested that this emission comes from an ionized region in a cool wind around the secondary. The characteristics of the emission, however, support the view that the lines are formed in a transition region around the late-type supergiant. A self-consistent model chromosphere and transition region are presented here as further evidence. A satisfactory model, taking into account the transition region material, the variable asymmetry in Mg II and the X-ray emission might be possible in terms if a hybrid supergiant with an X-ray illuminated cool wind