Aberration and advection effects in expanding spherically symmetric shells

The extreme outer layers of supernovae, novae, AGN, QSOs, and many supergiant stars are known to be in rapid expansion or contraction. In this paper, aberration and advection effects in a spherical medium scattering radiation isotropically and coherently are investigated. The shells are assumed to be moving radially with velocities of 1000, 2000, 3000, 4000, and 5000 km/s. A solution of the radiative transfer equation is presented. The changes in mean intensities are dependent on the geometrical and optical thickness and in particular depend on the ratio T/(B/A), where T is the maximum optical depth and B and A are the outer and inner radii of the spherical shell, respectively. 8 refs