Mass loss from the structured winds of hot, massive stars

Abstract by Jon Sundqvist
It is observationally as well as theoretically well-established that
the winds of hot, massive stars are highly structured on a broad range
of spatial scales. This talk first discusses consequences of the
small-scale structures associated with the strong instability inherent
to the line-driving of these winds. We demonstrate the importance of a
proper treatment of such wind clumping (including effects of optically
thick clumps and a non-monotonic velocity field) to accurately
interpret wind diagnostics and obtain reliable estimates of mass-loss
rates. But a growing subset of massive stars has also been found to
possess strong surface magnetic fields, which may channel the star's
wind outflow and so induce also large-scale structures and cyclic
behaviour of spectral diagnostics. The talk concludes by presenting
our recent result showing that multi-dimensional
magneto-hydrodynamical wind simulations together with detailed
radiative-transfer modeling remarkably well reproduce the periodic
Balmer emission observed in slowly rotating magnetic O stars.

Background Papers
"The nature and consequences of clumping in hot,
massive star winds"
Sundvist, Owocki, & Puls, 2011arXiv1110.0485S