Publications of the Astronomical Society of the Pacific
106: 949-963, 1994 September

             Multicolor Polarimetry of Selected Be Stars: 1990-93

                                 DAVID McDAVID

 Limber Observatory, Timber Creek Road, P.O. Box 63599, Pipe Creek,Texas 78063
                    Electronic mail: mcdavid@pinet.aip.org

     
     ABSTRACT.  Optical polarization data in the UBVRI filter system for
     eight bright northern Be stars are presented here as the continuation
     of a long-term monitoring project begun in 1984.  There are no strong
     cases of night-to-night variability, and the only star showing
     unmistakable changes in polarization from year to year over the nine
     years covered by the program is Pi Aquarii.  Even though the observed
     sample spans a wide range in spectral type, vsini, and degree of
     intrinsic polarization, the normalized wavelength dependence of the
     polarization is surprisingly similar for all of the stars.  Analysis
     of the wavelength dependence of the variable polarization of Pi Aqr in
     terms of a simple equatorial-disk model suggests that changes in the
     circumstellar electron number density alone may be sufficient to
     account for the observations, but it is not clear what real physical
     mechanism is involved.