Radiation pressure in resonance lines

Abstract

The effects of large scales gas motions on the radiation pressure in a resonance lines are investigated. We have assumed a medium with pure scattering together with emission in the continuum. A linear velocity law is employed with maximum velocity V=30mean thermal units at τ=0 and V=0 at τ = τ/submax. The geometrical thickness of the atmosphere B/A, (where B and A are the outer and inner radii of the atmosphere) are taken to be 3, 10 and 20. Total optical depths to those with smaller optical depths. When β (=KC/KL where KC and KL are absorption coefficients per unit frequency interval in the continuum and line respectively) changes as 1/ τ shell the radiation pressure falls off rapidly somewhere in the middle of the atmosphere and then starts to rise again.