What Line Profiles Can Tell Us
The wavelength of an emitted photon is proportional to the line-of-sight velocity:
Line shape maps emission at each velocity/wavelength interval
Continuum absorption by the cold stellar wind affects the line shape
Correlation between line-of-sight velocity and absorption optical depth will cause asymmetries in emission lines
The shapes of lines, if they’re broad, tells us about the distribution and velocity of the hot plasma in the wind -- maybe discriminate among specific wind shock models/mechanisms