084463

We propose to use the high throughput and high resolution capabilities of XMM-Newton to perform phase resolved spectroscopy of the extreme supergiant wind accretor XTE J1855 026. This will allow us to study the stellar wind structure and properties of the B supergiant donor throughdoublePoint aclosePar the reconstruction of the wind density stratification in a B0.5Ia luminous star comma bclosePar put observational constrains on the radial onset of wind clumping comma cclosePar explore the accretion physics at work and its interplay with the wind to explain the episodes of extreme brightness not seen in systems with similar donors.