Paper published in the proceedings of the Wrocław HELAS Workshop ``Interpretation of Asteroseismic Data'', CoAst, 157, 228 (Kochukhov 2008).Pulsational variability is observed in several types of main sequence stars with anomalous chemical abundances. In this contribution I summarize the relationship between pulsations and chemical peculiarities, giving special emphasis to rapid oscillations in magnetic Ap stars. These magneto-acoustic pulsators provide unique opportunities to study the interaction of pulsations, chemical inhomogeneities, and strong magnetic fields. Time-series monitoring of rapidly oscillating Ap stars using high-resolution spectrometers at large telescopes and ultra-precise space photometry has led to a number of important breakthroughs in our understanding of these interesting objects. Interpretation of the roAp frequency spectra has allowed constraining fundamental stellar parameters and probing poorly known properties of the stellar interiors. At the same time, investigation of the pulsational wave propagation in chemically stratified atmospheres of roAp stars has been used as a novel asteroseismic tool to study pulsations as a function of atmospheric height and to map in detail the horizontal structure of the magnetically-distorted p modes.
Communications in Asteroseismology
- Pub Date:
- March 2009
- Invited review presented at JENAM 2008 Symposium No.4 "Asteroseismology and stellar evolution", eds. S. Schuh and G. Handler., Communications in Asteroseismology, 159, in press