Effects of aberration and advection on line formation

Abstract

The effects of inclusion of the aberration and advection terms in the equation of the line transfer are studied. Spherical shells whose ratios of outer (B) to inner (A) radii (B/A) are 2, 5, and 10 and with line-center optical depths 500, 1300, and 1350 are considered. The velocities of expansion of the medium are set at 1000, 2000, 3000, 4000, and 5000 km/s. The line source functions and the corresponding profiles of lines are calculated. The individual and combined effects of the transverse and radial velocity gradients, and those of aberration and advection in plane-parallel and spherically symmetric geometries on the line source functions and the emerging line profiles are considered. It is found that large effects are generated in the radiation field when these physical mechanisms are taken into account in the transfer of the line radiation. The method for various velocity laws was tested and found to be stable.