Selection Rules for Perturbations to the Eigenfunctions of the Pulsations of Stars due to the Rotation and Magnetic Field
Abstract
We derive the selection rules for the perturbations to the eigenfunctions of stellar oscillations caused by stellar rigid rotation and axisymmetric poloidal magnetic fields. We introduce vector spherical harmonics in order to deal with the perturbation equation of motion, and show that they are useful to express the eigenfunctions of nonradial oscillations of stars. It is shown that if the magnetic fields are expressed by the multipole expansion series up to the order k, the eigenfunction of the mode with a spherical degree l and an azimuthal order m in the nonrotating, nonmagnetic case has components of the spherical degree max (l2k,0), ..., l+2k and the azimuthal order l, ..., l. We discuss the oscillation features of rapidly oscillating Ap stars, and interpret them as being a manifestation of a magnetic perturbation of the nonradial modes.} \kword{ Asteroseismology  Stars: magnetic  Stars: peculiar A  Stars: pulsation  Stars: rotation
 Publication:

Publications of the Astronomical Society of Japan
 Pub Date:
 June 1994
 Bibcode:
 1994PASJ...46..301T
 Keywords:

 Eigenvectors;
 Magnetic Fields;
 Magnetic Stars;
 Peculiar Stars;
 Perturbation;
 Stellar Oscillations;
 Stellar Rotation;
 Astrophysics