The equations of line transfer given in the Eqs. (1) and (2) are
solved following the procedure described in Peraiah et al. (1987).
The optical depths along these segments
are calculated
using the Eq. (1) of Paper I. We set
as the electron scattering coefficient equal
to (Thomson cross section) to
cm ^{2}. The lengths of the segments
change between 0 and 2*r* where *r* is the radius of the component.

We have set an electron density of 10

= ratio of the outer to the inner radii of the atmosphere of the primary component and whose reflection effect is being studied (=2);

*n* = number of shells into which the atmosphere of the component is
divided;

= ratio of the radius of the component to that of the line joining the centre of gravity of the two components cm;

*V*_{A} = initial velocity of expansion in units of mtu at *n* = 1 (see Eqs. (12) and (13));

*V*_{B} = final velocity in units of mtu at *n* = 100 (see Eq. (14));

*S* = total source function (see Eq. (8));

= source function due to self radiation;

*I* = ratio of incident radiation to that of self radiation of the
star (see Eq. (11));

= probability per scatter that a photon is thermalised by collisional de-excitation;

= ratio of absorption coefficient in continuum to that in the line;

*T* = total optical depth;

*Q* =
(see Eq. (15));

= ratio of the line flux at the normalized
frequency *Q* to that in the continuum or at
(see Eqs. (16) and (17)),

(*R*; *N*.*R*) = with reflection; with no reflection;

= height of the emission to the depth of absorption in the line;

*T*_{1} = temperature in the atmosphere;

= optical depth due to dust scattering (isotropic).

Our objective is to compute the effects of the presence of dust
on the formation of the spectral lines. The number of parameters is
large and this results in a large amount of output consequently we choose
few sample parameters to show the effects of dust on the formation of lines.
We have chosen trapezoidal points for frequency integration. We
employed nine frequency points (*I*=9) with one frequency point
at the centre of the line and two angles (*m*=2) in each half space which
gives a matrix
size of
.
With this size of frequency angle mesh, we obtain a step size
which gives solution to the machine accuracy. The condition
of flux conservation in a conservatively scattering medium
,
is maintained.

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