Below I illustrate typical line profile variation produced by different types of structures on the surfaces of rotating stars. I am doing Doppler Imaging analysis of all these different types of starspots.
|Temperature||Chemical abundance||Magnetic field||Non-radial pulsation|
Magnetic field Active late-type stars possess small scale,
structured magnetic fields. They can be detected and characterized using high-resolution spectroscopy combined with the analysis of circular
polarization. The Stokes V signatures of magnetic spots move across the line profile
and change in amplitude depending on the field orientation inside the spot (left).
Many hot stars exhibit very strong, globally-organized magnetic fields. Their magnetic geometries can be approximately described with a dipole inclined with respect to the stellar rotational axis. For such stars we can measure and interpret line profile variation in all four Stokes parameters. The Stokes V spectra provide information about the line of sight magnetic component while linear polarization spectra (Stokes Q and U) characterize the transverse magnetic field (right).