Abstract. The observed properties of the close binary AE Aqr indicate that the mass transfer in this system operates via the Roche lobe overflow mechanism, but the material transferred from the normal companion is neither accreted onto the surface of the white dwarf nor stored in a disk around its magnetosphere. As previously shown, such a situation can be realized if the white dwarf operates as a propeller. At the same time, the efficiency of the propeller action by the white dwarf is insufficient to explain the rapid braking of the white dwarf, which implies that the spin-down power is in excess of the bolometric luminosity of the system. To avoid this problem we have simulated the mass-transfer process in AE Aqr assuming that the observed braking of the white dwarf is governed by a pulsar-like spin-down mechanism. We show that the expected Hα Doppler tomogram in this case resembles the tomogram observed from the system. We find that the agreement between the simulated and the observed tomograms is rather good provided the mean value of the mass-transfer rate Ṁ ∼ 5 × 10 16 g s −1 . Three spatially separated sources of Hα emission can be distinguished within this approach. The structure of the tomogram depends on the relative contributions of these sources to the Hα emission and is expected to vary from night to night.

Abstract. We present the results of observations of the Herbig Ae star HD 31648 including high-resolution spectroscopy near the Hα, He  λ 5876 Å and DNa  lines, multi-color photometry and polarimetry. These observations have revealed many features of the observational appearance of HD 31648 similar to those of the "classical" Herbig Ae stars. Among them are spectral manifestations of both the mass loss and the disk accretion onto the star and certain types of line profile variations. The totality of the observed properties of HD 31648 provides evidence in favor of complicated structure in the stellar wind zone, exhibiting latitudinal stratification and containing local inhomogeneities in the form of outflowing streams and density condensations. Structural variations of the stellar wind have been found to correlate with changes in the accretion process in the envelope. The circumstellar environment of HD 31648 is supposed to contain dust particles of different forms manifesting themselves, in particular, in the variable multi-component intrinsic polarization.

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Abstract. We present new results of a spectroscopic and polarimetric investigation of the candidate young Herbig Ae/Be star HD 163296. Twenty two spectra of this object near the Hα, He i 5876 and DNa i lines had been obtained in 1992-1995 at the Astrophysical National Laboratory of Brazil (LNA). In addition, forty seven high-resolution spectra in Hα and Hβ were obtained at the ESO (Chile) in 1991-1992. VRI-polarimetry (about forty measurements of the Stokes parameters Q, U, V in each passband) were carried out at the SAAO (South Africa) in July 17-30, 1995.Striking profile variability has been found in all the lines on time scales from hours to months. Analysis of the profiles revealed manifestations of a remote cool shell which is in active interaction with the variable kinematically stratified stellar wind. Signs of cyclic positional variations of the Hα and Hβ emission peaks were observed during five nights in July, 1991.Sinusoidal variations of the linear polarization parameters detected in July, 1995 are explained in the framework of a model involving magnetized gaseous condensation, rotating in the envelope with the period of 15 days.Marginal detection of circular polarization is also reported.