EAS Publications Series

Stellar Evolution and Seismic Tools for Asteroseismology - Diffusive Processes in Stars and Seismic Analysis
C.W. Straka, Y. Lebreton and M.J.P.F.G. Monteiro (eds)
EAS Publications Series, 26 (2007) 111-119
DOI: 10.1051/eas:2007129

The Effects of Stellar Rotation and Magnetism on Oscillation Frequencies

D. Reese

Department of Applied Mathematics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK

(Published online: 20 June 2007)

Abstract

Stellar rotation and magnetism are two phenomena which intervene in many pulsating stars. As a result, calculating their effects on stellar pulsations has been the subject of active research for a number of years, and many results have emerged. For instance, slow stellar rotation lifts mode degeneracy and leads to evenly spaced frequency multiplets. At rapid rotation rates, a new organisation of the frequency spectrum appears, in which the centrifugal force plays a dominant role. Stellar magnetism plays an important role on pulsation frequencies both directly and indirectly. Various studies show how magnetism can shift frequencies and play on mode excitation and selection. Magnetism also introduces other types of waves with a different frequency spectrum organisation.