The nature of the strong, static polarization of the quasar OI 287

In this paper we present optical polarimetry, optical spectrophotometry, and infrared photometry of the highly polarized quasar OI 287. The principal observational results are as follows. 1. The polarization in the optical is 7% and has remained constant in magnitude and direction over a period of 8 yr. 2. The position angle of the polarization is identical to that of the extended radio structure. 3. The [O III] λλ4959, 5007 emission is polarized at the 2%-4% level with a similar position angle to that of the optical continuum. 4. OI 287 has a rich emission line spectrum showing both broad and narrow Balmer components and exceptionally strong [O III]. 5. The optical continuum rises steeply into the near infrared but flattens by 10 microns. The far-infrared does not dominate the optical/IR continuum luminosity. The observations indicate that the continuum emission in OI 287 is not intrinsically polarized but rather is reprocessed and polarized by scattering. A model incorporating a partial ring of dust which is highly inclined to the line of sight and is mixed with the gas of the narrow-line region is discussed.