Astron. Astrophys. 344, 607-613 (1999)

5. Conclusions

In this paper we presented new spectroscopic observations of the eclipsing symbiotic system SY Mus. The observations, done by IUE satellite, cover phase intervals before and after the total eclipse of the hot star. We obtained phase dependent flux for emission lines and continuum points where no significant emission lines were present. We also derived from the observations close to the eclipse the column densities of Rayleigh scattering.

Using the eclipse observations of hydrogen column densities we modeled the giant's cool wind velocity assuming neutrality as a first approximation. The velocity is reasonably well described by the empirical law given by Eq. (7). Probably this function is well adapted for modeling the neutral wind of other S-type symbiotic systems. The estimated mass-loss rate from the giant in SY Mus turned out to be lower than for most S-type systems with mass-loss rates derived from radio observations. This refers not only to our model given by Eq. (7) but also to the results from the application of Vogel's empirical law (V91) and the method developed by KDV93.

As pointed out before, our analysis assumes neutrality for the stellar wind. The column densities fall quite quickly near b=3. We cannot exclude the possibility that the ionization front of the hydrogen is exerting some influence in that range of the impact parameter. The modelling of the front could in principle set further constraints on the parameter a and therefore on the mass-loss rate of SY Mus.

© European Southern Observatory (ESO) 1999

Online publication: March 18, 1999
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