MULTICOLOR POLARIMETRY OF THE DUST DISK CANDIDATE BD -DEGREES-643(31)

The tentative detection of a dust disk around the main-sequence star B D+31 degrees 643 was recently announced by Kalas & Jewitt and represen ts only the second such object ever to be imaged. Here, we present mul tiband visual polarimetry of this object. Our single-aperture polarime try also strongly suggests the presence of a disk. We find that the po les of the disk are oriented parallel to the polarization of the major ity of background sources in the region and, hence, probably to the ma gnetic field in the cloud, as would be expected from star formation th eory. The polarization observed toward BD+31 degrees 643 can be modele d as a combination of Rayleigh scattering from material in the polar r egions of the disk and a term due to the disk itself.