Mass loss from inhomogeneous hot star winds II. Constraints from a combined optical/UV study

Abstract

Mass-loss rates currently in use for hot, massive stars have recently been seriously questioned, mainly because of the effects of wind clumping. We investigate the impact of clumping on diagnostic ultraviolet resonance and optical recombination lines. Optically thick clumps, a non-void interclump medium, and a non-monotonic velocity field are all accounted for in a single model. We used 2D and 3D stochastic and radiation-hydrodynamic (RH) wind models, constructed by assembling 1D snapshots in radially independent slices. To compute synthetic spectra, we developed and used detailed radiative transfer codes for both recombination lines (solving the "formal integral") and resonance lines (using a Monte-Carlo approach). In addition, we propose an analytic method to model these lines in clumpy winds, which does not rely on optically thin clumping. Results: Synthetic spectra calculated directly from current RH wind models of the line-driven instability are unable to in parallel reproduce strategic optical and ultraviolet lines for the Galactic O-supergiant LCep. Using our stochastic wind models, we obtain consistent fits essentially by increasing the clumping in the inner wind. A mass-loss rate is derived that is approximately two times lower than predicted by the line-driven wind theory, but much higher than the corresponding rate derived from spectra when assuming optically thin clumps. Our analytic formulation for line formation is used to demonstrate the potential impact of optically thick clumping in weak-winded stars and to confirm recent results that resonance doublets may be used as tracers of wind structure and optically thick clumping. (Abridged)

14 pages+1 Appendix, 8 figures, 3 tables. Accepted for publication in Astronomy and Astrophysics. One reference updated, minor typo in Appendix corrected

References in corpus (8)

• Physical Properties of Wolf-Rayet Stars
• Mass loss from hot massive stars
• Bright OB stars in the Galaxy - III. Constraints on the radial stratification of the clumping factor in hot star winds from a combined Halpha, IR and radio analysis
• Neglecting the porosity of hot-star winds can lead to underestimating mass-loss rates
• High resolution X-ray spectroscopy of bright O type stars
• On the Importance of the Interclump Medium for Superionization: O VI Formation in the Wind of Zeta Pup
• NLTE models of line-driven stellar winds III. Influence of X-ray radiation on wind structure of O stars
• Mass loss from OB-stars

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