The structure of line-driven winds

TL;DR

This paper models spherically-symmetric, singularity-free line-driven stellar winds for O stars, linking them to plane-parallel layers, and confirms outward information flow, enhancing understanding of stellar wind structures.

Contribution

It introduces singularity-free wind solutions that match previous layers and confirms outward wave propagation, improving the physical realism of stellar wind models.

Findings

Solutions are singularity-free, allowing fixed mass-loss rates.

Radiative-acoustic waves propagate outward at all points.

Flow is unaffected by inward wave motions, validating previous assumptions.

Abstract

Following procedures pioneered by Castor, Abbott & Klein (1975, [CAK]), spherically-symmetric supersonic winds for O stars are computed for matching to plane-parallel moving reversing layers (RL's) from Paper I (Lucy 2007). In contrast to a CAK wind, each of these solutions is singularity-free, thus allowing its mass-loss rate to be fixed by the regularity condition at the sonic point within the RL. Moreover, information propagation in these winds by radiative-acoustic waves is everywhere outwardly-directed, justifying the implicit assumption in Paper I that transonic flows are unaffected by inwardly-directed wave motions.