SHORT-TERM SPECTRAL AND POLARIMETRIC VARIABILITY IN THE HERBIG AE STAR AB AURIGAE AS AN INDICATOR OF THE CIRCUMSTELLAR INHOMOGENEITY

We present the results of the simultaneous spectral and polarimetric i nvestigation of AB Aur - the Ae Herbig star from the ''PCyg'' subclass . About 150 high-resolution CCD spectra in the region of H alpha and m ore than 100 UBVRI measurements of the linear polarization were obtain ed at the Crimean Astrophysical Observatory during two seasons in 1993 and 1994. Additional polarimetric observations in the B-band were car ried out at the Special Astrophysical Observatory (Northern Caucasus). A strong variability of the H alpha PCyg-type profile is analyzed on a timescale from hours to months. It is shown to be connected with cir cumstellar inhomogeneities moving in the envelope. The existence of a strong long-lived stream is supposed on the basis of joint spectral an d polarimetric data in January 4-10, 1994.