Asteroseismology of magnetic A stars - towards a 3-D view of stellar atmospheres
by
Oleg Kochukhov(Uppsala University)
→
Europe/Stockholm
FA 31
FA 31
Description
Pulsational variability is observed in many different types of stars across the
H-R diagram. Magneto-acoustic p-mode oscillations in chemically peculiar A stars
are of particular interest due to unique opportunities to study the interaction
of pulsations, chemical inhomogeneities, and strong magnetic fields. In this ta
lk I will review recent progress in our understanding of these interesting objec
ts achieved through time-series spectroscopy at large telescopes and ultra-preci
se photometry from space. In particular, interpretation of the pulsation frequen
cy spectra has allowed to constrain stellar parameters and to probe poorly known
interior magnetic geometries and chemical composition. At the same time, studie
s of variability in individual spectral lines allowed to trace pulsational wave
propagation in compositionally stratified atmospheres and to map pulsations and
chemical abundances as a function of atmospheric height. Combining this new seis
mic tomography approach with the Doppler imaging analysis of the horizontal puls
ation and chemical structure opens prospects of first 3-D maps of stellar atmosp
heres.
