Constraining the properties of the post-RLOF massive binary HD149404

HD149404 is an O7.5If + ON9.7I binary that has experienced a Case A Roche lobeoverflow episode. Although the system has been studied intensively in theoptical and UV, the orbital inclination as well as the wind parameters remainpoorly constrained. The Xray emission from the windwind interaction betweenthe stars should be modulated by a changing wind column density as the starsrevolve around each other. We propose three observations, of 25 ks each: twoscheduled at conjunction phases, and one observation near quadrature. Usingthese three spectra, it is possible to establish the variations of the absorbingcolumn density and hence to constrain the orbital inclination, the wind momentumratio and the radial extent of the wind interaction zone. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]