A change in the mass-loss rate leads to a change in the neutral-hydrogen
column seen by the parent photon, and hence the scattering and
absorption optical depths. The Raman photons will therefore originate
in different parts of the wind for different mass-loss rates, and the
line profiles will reflect this. Four models were computed in order to
investigate this sensitivity, using mass-loss rates of 
and -8 (Fig. 13 (click here)).
The morphology of the 
(reference-model) polarization profile was discussed earlier.
The intensity profile of the 
model shows a two-peaked
intensity structure, with the bluewards peak centred at the Raman-line
rest wavelength, showing that it is a result of photospheric scattering.
The polarized flux is triple-peaked, with all the peaks polarized in the
same direction; there is no polarization flip. The three peaks
originate in the material between the two stars (approaching the
OVI source), in the red-giant photosphere, and in the region
`behind' the red giant (as seen from the hot component). There is,
relatively speaking, insufficient material `above' and `below' the hot
component to introduce significant features at orthogonal polarizations.
This interpretation is confirmed by the 
model, which
shows a two-peaked intensity profile, with the bluewards peak the
strongest. This peak corresponds to photospheric scattering; there is
very little scattering in the rarified wind. The polarized flux peak
again occurs at the Raman-line rest wavelength, and is a result of
photospheric scattering. The very small redward peak is associated with
wind scattering in the extended region `behind' the red giant.
The 
model has a higher intensity than the reference
model, and shows a four-peaked structure in polarized flux. The first
three peaks (going from blue to red) have the same interpretation as in
the reference model, with no significant photospheric scattering. The
redmost peak arises because there is sufficient wind density the allow
multiple scatterings from `above' to `below' the hot component (and vice
versa). As expected, therefore, the mass-loss rate (or, more strictly,
the density distribution) has a dramatic effect on both the Raman-line
intensity and its polarization morphology.