UBVRI photopolarimetry of the long period eclipsing AM Herculis binary   V1309
  We report simultaneous UBVRI photo-polarimetric observations of the long period (7.98 h) AM Her binary V1309 Ori. The length and shape of the eclipse ingress and egress varies from night to night. We suggest this is due to the variation in the brightness of the accretion stream. By comparing the phases of circular polarization zero-crossovers with previous observations, we confirm that V1309 Ori is well synchronized, and find an upper limit of 0.002 percent for the difference between the spin and orbital periods. We model the polarimetry data using a model consisting of two cyclotron emission regions at almost diametrically opposite locations, and centered at colatitude 35 (deg) and 145 (deg) on the surface of the white dwarf. We also present archive X-ray observations which show that the negatively polarised accretion region is X-ray bright. 
S. Katajainen (1), V.Piirola (1), G.Ramsay (2), F. Scaltriti (3),   H.J.Lehto (1,4), M. Cropper (2), M. K. Harrop-Allin (2),...