Pulsations of Complete Evolutionary Models for roAp Stars: Preliminary Results

Extract

The evolutionary models described in the accompanying poster (Richard et al., these proceedings) have been tested for pulsations using both the adiabatic code developed by Brassard et al. (1992) and the corresponding non-adiabatic code as first used in Fontaine et al. (1994). For the stars of interest, these codes have the great advantages of being potentially able to treat atmospheric regions, as well as being numerically stable and efficient. The required derivatives were calculated by least-square fitting of spline functions to complete opacity tables constructed at each composition of the evolved model. Since there were some 1500 zones for each model, 1500 such tables were constructed and spline functions were fitted to each of them. They then gave directly the derivatives required for the pulsation calculations (see Fig. 1). Note that models equivalent to 1.70T5.3D1K-3 have already been tested for pulsations by Turcotte et al. (2000).