Chandra X-ray Observatory grating spectra of the supergiant X-ray Binary 4U 1700-37 reveal emission lines from hydrogen and helium-like S , Si , Mg , and Ne in the 4–13 Å range .
The spectrum also shows fluorescent lines from S , Si , and a prominent Fe K \alpha line at 1.94Å .
The lines contribute to the previously unaccounted “ soft excess ” in the flux in this range at orbital \phi \approx 0.7 .
The X-ray source was observed during intermittent flaring , and the strengths of the lines vary with the source state .
The widths of the lines ( FWHM \approx 1000 - 2000 km/s ) can result from either Compton scattering or Doppler shifts .
Power spectra of the hard X-rays show red noise and the soft X-rays and lines show in addition quasiperiodic oscillations ( QPOs ) and a power-spectral break .
Helium-like triplets of Si and Mg suggest that the gas is not in a pure photoionization equilibrium .
We discuss whether resonant scattering could affect the line ratios or whether a portion of the wind may be heated to temperatures T \sim 10 ^ { 6 } K .