Astron. Astrophys. Suppl. Ser. 145, 525-532
Radiative transfer in the dusty, irradiated expanding atmospheres of close binary components
M. Srinivasa Rao1 -
Send offprint request: M. Srinivasa Rao
Indian Institute of Astrophysics, Bangalore-560034, India
Madiwala-Dollar Scheme, Bangalore 560068, India
Received April 25; accepted June 13, 2000
We studied the formation of lines in the irradiated
expanding dusty atmospheres of the components of close binary
systems. We considered a two-level atom approximation in
Non-LTE situation with complete redistribution. The thickness of
the atmosphere is set to
be equal to twice that of the stellar radius. Maximum expansion velocities is
set to be as large as 50 mean thermal units.
The isotropically scattering dust is distributed uniformly in the
We have computed the
lines using a total optical depths 104
at the line
centre. The irradiation from the secondary is one, five
and ten times the self radiation. The line fluxes in the
line of sight are calculated by using the total source function
which is the sum of the source functions due to self radiation
and that due to irradiation from the secondary. The line profiles formed in dusty
atmosphere are compared with those formed in dust free atmosphere.
The profiles are presented for different velocities of expansion, different
separations between the components and several dust optical depths.
P Cygni type profiles are produced in the expanding atmosphere and the
irradiation from the secondary enhances the emission in the lines.
The major effect of dust on the formation of lines in the
expanding atmospheres of the component of close binary is to scatter
photons into the line core, among others.
Key words: radiative transfer -- close binaries --
reflection effect -- dust
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