Quasi-simultaneous optical and IR photometric (BVRIJHK) and optical polarimetric (BVRI) observations were carried out at the 1 m telescope of Assy Observatory (Institute of Astrophysics of the Kazakhstan Academy of Sciences). The photometer-polarimeter of the Pulkovo Observatory (Bergner et al. 1988) was used for the study. All our measurements were done with apertures of 26" and 52".

HDE 259431. Our data show a strong polarimetric variability Δp = 2% – 3% and ΔΘ 30° (especially in UV and optical region). Although the general nature of polarization is connected with the dust disk around the star (Dzhakusheva et al. 1988), the polarimetric variability probably has an another origin. This is due to the fact that we have observed a strong polarimetric variability on a time-scale of up to several hours (Dzhakusheva et al. 1988). Incidentally, this rapid polarimetric variability has no correspondence in photometry.