1997A&A...327..648D

The High Speed Photometer (HSP) on the Hubble Space Telescope observed SS 433 at 15 different epochs between 1993 May and November. Polarimetric observations were obtained in a 340Å FWHM bandpass centered at 2770Å; photometric observations were made in a bandpass extending between 1400 and 3000Å. The polarization in the UV is both large (<p≥13±4%) and variable. Observations at the 6-m telescope of the Special Astrophysical Observatory find the polarization in the U band to be intermediate in magnitude between that in the V band and that we detect in the UV. These results are best explained by the existence of a Rayleigh scattering component in the polarized radiation. Less than 1.2% of the flux from SS 433 between 1400 and 3000Å is modulated with a period between 200µs and 100s at 164-d phase ψ=0.131, when the two sets of emission lines in the SS 433 spectrum have a local maximum in the separation of their redshifts.