We present a discussion of theoretical absorption line Stokes profiles of magnetic stars within the framework of the rigid rotator model. Our calculations reveal the occurrence of asymmetric absorption line profiles in the Stokes I parameter at certain phases of the magnetic cycle, confirming and extending Borra’s (1974) results. This effect results from the combination of a dipolar magnetic field structure and moderate rotational velocities and is shown to be closely related to the well-known crossover-effect. Theoretical line profiles calculated for a large number of combinations of excentric dipole models, magnetic field strengths, phases, rotational velocities, oscillator strengths and atomic transitions are then investigated in order to determine the changes in asymmetry and degree of crossover as a function of these parameters. Finally, we point out possible applications of the absorption line asymmetries to the determination of stellar magnetic fields.
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M. J. Stift (1985) studied this question.