  The high-mass X-ray binary 4U1700-37/HD153919 has been observed with FUSE to
study the effect of the X-ray source on the stellar wind of the primary. Phase
dependent changes in the wind lines have been observed, indicating the creation
of a X-ray ionization zone in the stellar wind. The X-ray luminosity of
4U1700-37 ionizes much of the wind and leaves a Stromgren zone. This disrupts
the resonance-line acceleration of the wind in portions of the orbit, quenching
the wind and disrupting the mass flow. This effect was found for the first time
in 4U1700-37. This so-called Hatchett-McCray (HM) effect had been predicted for
4U1700-37, but was not previously detected.
