The analysis of hard X-ray INTEGRAL observations ( 2003-2008 ) of superaccreting galactic microquasar SS433 at precessional phases of the source with the maximum disk opening angle is carried out .
It is found that the shape and width of the primary X-ray eclipse is strongly variable suggesting additional absorption in dense stellar wind and gas outflows from the optical A7I-component and the wind-wind collision region .
The independence of the observed hard X-ray spectrum on the accretion disk precessional phase suggests that hard X-ray emission ( 20 - 100 keV ) is formed in an extended , hot , quasi-isothermal corona , probably heated by interaction of relativistic jet with inhomogeneous wind outflow from the precessing supercritical accretion disk .
A joint modeling of X-ray eclipsing and precessional hard X-ray variability of SS433 revealed by INTEGRAL by a geometrical model suggests the binary mass ratio q = m _ { x } / m _ { v } \simeq 0.25 \div 0.5 .
The absolute minimum of joint orbital and precessional \chi ^ { 2 } residuals is reached at q \simeq 0.3 .
The found binary mass ratio range allows us to explain the substantial precessional variability of the minimum brightness at the middle of the primary optical eclipse .
For the mass function of the optical star f _ { v } = 0.268 M _ { \odot } as derived from Hillwig & Gies data , the obtained value of q \simeq 0.3 yields the masses of the components m _ { x } \simeq 5.3 M _ { \odot } , m _ { v } \simeq 17.7 M _ { \odot } , confirming the black hole nature of the compact object in SS433 .