We present a unified picture of outflowing gas from the X-ray binary system Hercules X-1/HZ Herculis .
We suggest that the outflowing gas ( a wind ) causes UV emission seen in mid-eclipse , narrow UV absorption lines , and broad UV P Cygni lines .
Observations with the FOS and STIS spectrographs on the Hubble Space Telescope ( HST ) show UV emission lines in the middle of X-ray eclipse , when the X-ray heated atmosphere of the normal star and accretion disk should be entirely hidden from view .
Narrow absorption lines ( FWHM \approx 50 km s { -1 } ) blueshifted by 500 km s ^ { -1 } during observations in 1998 and by 400 km s ^ { -1 } during observations in 1999 were seen from \phi = 0. -0.3 .
The line velocity was constant to within 20 km s ^ { -1 } .
The P Cygni profiles from Hercules X-1 have optical depths \tau \mathrel { < \kern - 10.0 pt \lower 3.87 pt \hbox { $ \sim$ } } 1 with a maximum expansion velocity of \approx 600 km s ^ { -1 } , and are seen in the resonance lines N v \lambda \lambda 1238.8 , 1242.8 , Si iv \lambda \lambda 1393.7 , 1402.8 , and C iv \lambda \lambda 1548.2 , 1550.8 .
We discuss whether this wind originates in the accretion disk or on the companion star , and how the relevant ions can survive X-ray ionization by the neutron star .