Polarimetric Studies of Azimuthal Magnetic Inhomogeneities in the Envelopes of Herbig Ae/Be Stars

We discuss a technique for studying local gas inhomogeneities in the envelopes of young stars based on multicolor polarimetric observations. The method considered is based on the comparison of the observed time tracks of the variations in the Stokes parameters in the plane with the theoretical tracks computed in terms of a simple inhomogeneity model in the form of a gaseous stream with local magnetic field in the rotating envelope of a young star. The computations take into account the process of single scattering of radiation in the electron gas and the Faraday rotation of the polarization plane during propagation of radiation in a medium with magnetic field. The results of our computations depend strongly on the orbital inclination of the inhomogeneity to the line of sight and on the parameters of its magnetic field, whose influence on the polarization parameters increases with wavelength of radiation. The application of the method to the study of inhomogeneities in the envelopes of Herbig stars AB Aur and HD 163296 is described.