Nonlocal radiative coupling in non monotonic stellar winds

Abstract

There is strong observational evidence of shocks and clumping in radiation-driven stellar winds from hot, luminous stars. The resulting non monotonic velocity law allows for radiative coupling between distant locations, which is so far not accounted for in hydrodynamic wind simulations. In the present paper, we determine the Sobolev source function and radiative line force in the presence of radiative coupling in spherically symmetric flows, extending the geometry-free formalism of Rybicki and Hummer (1978) to the case of three-point coupling, which can result from, e.g., corotating interaction regions, wind shocks, or mass overloading. For a simple model of an overloaded wind, we find that, surprisingly, the flow decelerates at all radii above a certain height when nonlocal radiative coupling is accounted for. We discuss whether radiation-driven winds might in general not be able to re-accelerate after a non monotonicity has occurred in the velocity law.

accepted by A&A, 8 pages, 4 figures

References in corpus (3)

• Hydrodynamical Simulations of Corotating Interaction Regions and Discrete Absorption Components in Rotating O-Star Winds
• Stagnation and Infall of Dense Clumps in the Stellar Wind of tau Scorpii
• Co-moving frame radiative transfer in spherical media with arbitrary velocity fields

Cited by in corpus (5)

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• Mass-loss and diffusion in subdwarf B stars and hot white dwarfs: do weak winds exist?
• X-ray irradiation of the winds in binaries with massive components
• Stellar wind models of subluminous hot stars
• A Nozzle Analysis of Slow-Acceleration Solutions in One-Dimensional Models of Rotating Hot-Star Winds