Issue |
Astron. Astrophys. Suppl. Ser.
Volume 121, Number 1, January 1997
|
|
---|---|---|
Page(s) | 15 - 44 | |
DOI | https://doi.org/10.1051/aas:1997110 | |
Published online | 15 January 1997 |
Raman scattering in symbiotic stars. II. Numerical models
1
School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, Scotland
2
Dept. of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
Corresponding author: Send offprint request to: Tim Harries, email: tjh@st-and.ac.uk
Received:
27
December
1995
Accepted:
20
April
1996
We present numerical models of Raman-line formation in symbiotic
systems, based on Monte-Carlo simulations of scattering of
O
vi 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.
Key words: stars: binaries: symbiotic / stars: mass-loss / polarization
© European Southern Observatory (ESO), 1997