A Clumping Independent Diagnostic of Stellar Mass-loss Rates: Rapid Clump Destruction in Adiabatic Colliding Winds

Abstract

Clumping in hot star winds can significantly affect estimates of mass-loss rates, the inferred evolution of the star and the environmental impact of the wind. A hydrodynamical simulation of a colliding winds binary (CWB) with clumpy winds reveals that the clumps are rapidly destroyed after passing through the confining shocks of the wind-wind collision region (WCR) for reasonable parameters of the clumps if the flow in the WCR is adiabatic. Despite large density and temperature fluctuations in the post-shock gas, the overall effect of the interaction is to smooth the existing structure in the winds. Averaged over the entire interaction region, the resulting X-ray emission is very similar to that from the collision of smooth winds. The insensitivity of the X-ray emission to clumping suggests it is an excellent diagnostic of the stellar mass-loss rates in wide CWBs, and may prove to be a useful addition to existing techniques for deriving mass-loss rates, many of which are extremely sensitive to clumping. Clumpy winds also have implications for a variety of phenomena at the WCR: particle acceleration may occur throughout the WCR due to supersonic MHD turbulence, re-acceleration at multiple shocks, and re-connection; a statistical description of the properties of the WCR may be required for studies of non-equilibrium ionization and the rate of electron heating; and the physical mixing of the two winds will be enhanced, as seems necessary to trigger dust formation.

4 pages, 3 figures, accepted for publication in ApJL

References in corpus (5)

• 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
• The Effect of Porosity on X-ray Emission Line Profiles from Hot-Star Winds
• Radio, X-ray, and gamma-ray Emission Models of the Colliding Winds Binary WR 140
• High resolution X-ray spectroscopy of bright O type stars
• Origin of Structures in Wolf-Rayet Winds: FUSE Observations of WR 135

Cited by in corpus (20)

• Probing clumpy stellar winds with a neutron star
• A 3D dynamical model of the colliding winds in binary systems
• The turbulent destruction of clouds - I. A k-epsilon treatment of turbulence in 2D models of adiabatic shock-cloud interactions
• Asymptotic Opening Angles for Colliding-Wind Bow Shocks: the Characteristic-Angle Approximation
• Hard X-ray identification of Eta Carinae and steadiness close to periastron
• Simulations of an inhomogeneous stellar wind interacting with a pulsar wind in a binary system
• Hydrodynamic Winds From Twin-Star Binaries
• Competitive X-ray and Optical Cooling in the Collisionless Shocks of WR 140
• Colliding stellar wind modelling of the X-ray emission from WR 140
• Modeling the effects of clumpy winds in the high-energy light curves of γ-ray binaries
• Dynamic Imprints of Colliding-wind Dust Formation from WR140
• Puzzling X-rays from the new colliding wind binary WR65
• Prediction for the He I 10830A Absorption Wing in the Coming Event of Eta Carinae
• The First Candidate Colliding-Wind Binary in M33
• X-rays from the colliding wind binary WR 146
• Variable millimetre radiation from the colliding-wind binary Cyg OB2 #8A
• A global view on the colliding-wind binary WR 147
• The colliding-wind binary HD 168112
• X-ray plasma flow and turbulence in the colliding winds of WR140
• Eta Carinae: an evolving view of the central binary, its interacting winds and its foreground ejecta