A Polarimetric Study of the B[e] star HD 45677

Abstract

We present new medium-resolution spectropolarimetric observations of HD 45677 in the B and R-bands. A change in polarisation is detected across Halpha, Hbeta and Hgamma confirming that the ionised region around the star is aspherical. (Q,U) points associated with these emission lines occur away from the continuum, defining a polarisation vector which points in the same direction for each of the lines at an average intrinsic polarisation angle of 164 +/- 3 degrees. These data were combined with past photometric and polarimetric data from the literature to investigate any variability. We find that HD 45677 is both photometrically and polarimetrically variable and that these changes are linked. We suggest that these variations may be caused by an aspherical blowout and by deriving a least-squares fit to the B-band polarimetric data in Q-U space, we show that the blowout occurs at an intrinsic polarisation angle of 175 +/- 1 degrees, along the same angle as the proposed geometry of the ionised region.