STELLAR-WIND STRUCTURE IN HIGH-MASS X-RAY BINARIES comma PART 1

we propose iso observations to derive the nearinfrared energy distribution of highmass xray binaries (hmxbs) in order to study the velocity and density structure of the disrupted stellar wind. infrared freefree and freebound emission is formed in the inner wind regions where the major part of the acceleration takes place. this radiation is modelled rather straightforwardly and is relatively independent of parameters such as the level of ionization and the temperature of the wind that are difficult to determine. xray, uv and optical observations have suggested that the stellar wind leaving the massive companion is highly distorted in the direction of the xray source. an extended stromgren zone surrounds the xray source and trails the compact star in its orbit. inside this zone the radiative acceleration drops leading to the formation of a large and dense shock front in the wind. in general, the stellar wind is expected to be inhomogeneous, which might explain the observed xray variability, and focussed towards the xray source. infrared observations at different orbital phases will enable us to determine the detailed wind structure and the deviations with respect to undisturbed stellar winds. these observations will provide better insight in the hydrodynamics of radiationdriven winds in this extreme regime and the nature of the interactive accretion proces. the predicted ir flux of these systems is just below the sensitivity limit of iras, but easily feasible with iso. the large extinction in the direction of these systems makes the infrared wavelength domain uniquely suited to study their stellarwind structure. we will apply for coordinated observations with xray, uv and optical telescopes. the scientific goals of this proposal can be reached with iso observations only. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]