A polarimetric investigation of the eclipsing binary XY ursae majoris

On three nights in February 1976 we carried out polarimetric measurements, in V, of the short periodic eclipsing binary XY UMa, covering a complete cycle. The results are as follows:(1)Within all phase intervals the linear polarization does not exceed 0.1%.(2)In the phase range 0^p.95–1^p.35 the scatter of the Stokes parametersQ andU is about twice that within the phase interval 0^p.35–0^p.95.(3)A periodogram analysis of these data revealed a period of 21000 s, which is equal to half the orbital periodP_o=0^d.47899 within 1.5%.