A theoretical tool for the study of radial velocities in the atmospheres of roAp stars
Paola Quitral (Instituto de Astrofísica e Ciências do Espaço, U.Porto), Margarida S. Cunha (nstituto de Astrofísica e Ciências do Espaço, U.Porto)

Studies of high-resolution spectroscopy of rapidly oscillating Ap (roAp) stars show that the pulsations in these stars have a complex behavior in the atmospheric region, which results from their magnetoacoustic nature. Aiming at a better understanding of these pulsations, we developed a theoretical tool for the computation of the integrated radial velocities in roAp stars, as a function of depth. In the computation, we consider that the star is permeated by a dipolar magnetic field. The displacement at each latitude and depth is obtained with the MAPPA code (Cunha 2006) and we verify that the solutions for the outer atmosphere tend to the decoupled acoustic and magnetic analytic solutions valid for an isothermal atmosphere (Sousa & Cunha 2011). We explore the amplitude and phase behaviour derived from the theoretical radial velocities, for different mode degrees and different inclinations of the observer.