Far Ultraviolet Observations of the High-Mass X-Ray Binary 4U1700-37/HD153919

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 an 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, quenches the wind and stalls the mass flow. This is the so-called Hatchett-McCray effect that had been predicted for 4U1700-37, but was not previously detected.