Context :

Aims : Our aim is to study the mass transfer , accretion environment , and wind outflows in the SS 433 system , concentrating on the so-called stationary lines .

Methods : We used archival high-resolution ( XSHOOTER ) and medium-resolution ( EMMI ) optical spectra , new optical multi-filter polarimetry , and low resolution optical spectra ( Liverpool Telescope ) , spanning an interval of a decade and a broad range of precessional and orbital phases , to derive the dynamical properties of the system .

Results : Using optical interstellar absorption lines and H I 21 cm profiles , we derive E ( B-V ) =0.86 \pm 0.10 , with an upper limit of E ( B-V ) =1.8 \pm 0.1 based on optical Diffuse Interstellar Bands .
We obtain revised values for the ultraviolet and U band polarizations and polarization angles ( PA ) , based on a new calibrator star at nearly the same distance as SS 433 that corrects the published measurement and yields the same position angle ( PA ) as the optical .
The polarization wavelength dependence is consistent with optical-dominating electron scattering with a Rayleigh component in U and the UV filters .
No significant phase modulation was found for PA while there is significant variability in the polarization level .
We fortuitously caught a flare event ; no polarization changes were observed but we confirm the previously reported associated emission line variations .
Studying profile modulation of multiple lines of H I , He I , O I , Na I , Si II , Ca II , Fe II with precessional and orbital phase , we derive properties for the accretion disk and present evidence for a strong disk wind , extending published results .
Using transition-dependent systemic velocities , we probe the velocity gradient of the wind , and demonstrate that it is also variable on timescales unrelated to the orbit .
Using the rotational velocity , around 140 \pm 20 km s ^ { -1 } , a redetermined mass ratio q = 0.37 \pm 0.04 , and masses M _ { X } = 4.2 \pm 0.4 M _ { \odot } , M _ { A } = 11.3 \pm 0.6 M _ { \odot } , the radius of the A star fills – or slightly overfills – its Roche surface .
We devote particular attention to the O I 7772 Å and 8446 Å lines , finding that they show different but related orbital and precessional modulation and there is no evidence for a circumbinary component .
The spectral line profile variability can , in general , be understood with an ionization stratified outflow predicted by thermal wind modeling , modulated by different lines of sight through the disk produced by its precession .
The wind can also account for an extended equatorial structure detected at long wavelength .

Conclusions :