2002MNRAS.334..974Y

We compute the profiles of resonance doublet lines (S_1/2 -P_1/2,3/2) formed in bipolar winds with velocity greater than the doublet separation in symbiotic stars. Particular attention has been paid to the doublet line ratio, where an essential role is played by the conversion of the short-wavelength component arising from the S_1/2 -P_3/2 transition into the long-wavelength component for the transition S_1/2 -P_1/2 . We adopted a Monte Carlo technique and the Sobolev approximation. Our bipolar winds take the form of a cone and are characterized by the terminal wind velocity, the mass-loss rate and the opening angle of the cone. When an observer is in the polar direction and the Sobolev optical depth τ_Sob ≃ 1, we mainly obtain profiles with inverted flux line ratios, where the short-wavelength component is weaker than the long-wavelength component. When an observer is in the equatorial direction, we find that the profiles are characterized by two broad components, where the long-wavelength component is the broader and stronger of the two. We conclude that the profiles obtained in our model provide a qualitative understanding of the broad profiles and inverted intensity ratios of the doublets in symbiotic stars.