Abstract: | We have investigated the effects of increasing optical depths on spectral lines formed in a rotating and expanding spherical
shell. We have assumed a shell whose outer radius is 3 times the inner radius, with the radial optical depths equal to 10,
50, 100, 500. We have employed a constant velocity with no velocity gradients in the shell. The shell is assumed to be rotating
with velocities varying as 1/ρ, whereρ is the perpendicular distance from the axis of rotation, implying the conservation of angular momentum. Two expansion (radial)
velocities are treated: (1)V = 0 (static case) and (2)V = 10 mean thermal units. The maximum rotational velocities areV
rot = 0, 5, 10 and 20. In the shell where there are no radial motions, we obtain symmetric lines with emission in the wings forV
rot = 0 and 5 while forV
rot ≥ 10 we obtain symmetric absorption lines. In the case of an expanding shell, we obtain lines with central emission. |