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A&A Supplement series, Vol. 121, January 1997, 15 - 44

Received December 27, 1995; accepted April 20, 1996

Raman scattering in symbiotic stars. II. Numerical models

T.J. Harriestex2html_wrap3023 - I.D. Howarthtex2html_wrap3025

Send offprint request: Tim Harries (

tex2html_wrap3027  School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, Scotland
tex2html_wrap3029  Dept. of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK


We present numerical models of Raman-line formation in symbiotic systems, based on Monte-Carlo simulations of scattering of OVI resonance-line photons from a hot source in the extended, expanding atmosphere of a cool companion, and we explore the sensitivity of the model results to the input parameters. The model successfully reproduces the observed line ratios, velocities, and polarizations, and the viewing-angle (orbital) dependence of the line strengths and polarized intensities. In principle, the position-angle dependence of the polarization in resolved Raman lines provides a diagnostic of the extent of the ionized region in symbiotic systems; however, axisymmetric geometries with `up-down' symmetry, such as we use, fail to reproduce the most commonly observed dependence of PA on velocity. Raman-line polarization morphology is shown to be a powerful probe of the conditions in the red-giant wind; this is particularly true if observations are available at different orbital phases, so that geometrical and physical variables may more easily be isolated.

keywords: stars: binaries: symbiotic -- stars: mass-loss -- polarization

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