dotted line is interstellar.
Wind opacity for canonical B star abundances.
We do expect some
wavelength dependence of the cross
sections (and thus of the wind
optical depth), BUT the lines we
fit cover only a modest range of wavelengths. And in the case of z Pup, nitrogen overabundance (not in calculation shown
at right) could flatten out the
wavelength dependence even more.
OR perhaps clumping plays
a role. And clumping (alt. “porosity”) certainly could
play a role in the overall
reduction of wind optical depth.