Macroclumping as solution of the discrepancy between Hα and P v mass loss diagnostics for O-type stars

Abstract

Recent studies of O-type stars demonstrated that discrepant mass-loss rates are obtained when different diagnostic methods are employed - fitting the unsaturated UV resonance lines (e.g. P v) gives drastically lower values than obtained from the Hα emission. Wind clumping may be the main cause for this discrepancy. In a previous paper, we have presented 3-D Monte-Carlo calculations for the formation of scattering lines in a clumped stellar wind. In the present paper we select five O-type supergiants (from O4 to O7) and test whether the reported discrepancies can be resolved this way. In the first step, the analyses start with simulating the observed spectra with Potsdam Wolf-Rayet (PoWR) non-LTE model atmospheres. The mass-loss rates are adjusted to fit best to the observed Hα emission lines. For the unsaturated UV resonance lines (i.e. P v) we then apply our 3-D Monte-Carlo code, which can account for wind clumps of any optical depths, a non-void inter-clump medium, and a velocity dispersion inside the clumps. The ionization stratifications and underlying photospheric spectra are adopted from the PoWR models. From fitting the observed resonance line profiles, the properties of the wind clumps are constrained. Our results show that with the mass-loss rates that fit Hα (and other Balmer and He II lines), the UV resonance lines (especially the unsaturated doublet of P v) can also be reproduced without problem when macroclumping is taken into account. There is no need to artificially reduce the mass-loss rates, nor to assume a sub-solar phosphorus abundance or an extremely high clumping factor, contrary to what was claimed by other authors. These consistent mass-loss rates are lower by a factor of 1.3 to 2.6, compared to the mass-loss rate recipe from Vink et al. Macroclumping resolves the previously reported discrepancy between Hα and P v mass-loss diagnostics.

18 pages, 14 figures, 5 tables, accepted for publication in Astrononomy & Astrophysics

References in corpus (10)

• 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
• An Extensive Collection of Stellar Wind X-ray Source Region Emission Line Parameters,Temperatures, Velocities, and Their Radial Distributions as Obtained from Chandra Observations of 17 OB Stars
• Adaptive Optics Photometry and Astrometry of Binary Stars. III. A Faint Companion Search of O-Star Systems
• Direct spectroscopic observations of clumping in O-star winds
• 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
• The Correlation between X-Ray Line Ionization and Optical Spectral Types of the OB Stars

Cited by in corpus (78)

• Formation of Double Neutron Star Systems
• A coordinated X-ray and Optical Campaign of the Nearest Massive Eclipsing Binary, $\delta$ Orionis Aa: IV. A multiwavelength, non-LTE spectroscopic analysis
• High-Mass X-ray Binaries in the Milky Way: A closer look with INTEGRAL
• The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence
• Towards a unified view of inhomogeneous stellar winds in isolated supergiant stars and supergiant high mass X-ray binaries
• New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars II. A grid of O-type stars in the Galaxy and the Magellanic Clouds
• The R136 star cluster dissected with Hubble Space Telescope/STIS. III. The most massive stars and their clumped winds
• Theory and Diagnostics of Hot Star Mass Loss
• Magnetic massive stars as progenitors of "heavy" stellar-mass black holes
• Wolf-Rayet stars in the Small Magellanic Cloud: II. Analysis of the binaries
• Monte Carlo Radiative Transfer
• Metallicity-dependent wind parameter predictions for OB stars
• The VLT-FLAMES Tarantula Survey XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus
• Atmospheric NLTE-models for the spectroscopic analysis of blue stars with winds. IV. Porosity in physical and velocity space
• New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars. I. Method and first results
• Stellar population of the superbubble N206 in the LMC II. Parameters of the OB and WR stars, and the total massive star feedback
• Mass loss from inhomogeneous hot star winds III. An effective-opacity formalism for line radiative transfer in accelerating, clumped two-component media, and first results on theory and diagnostics
• Coupling hydrodynamics with comoving frame radiative transfer: II. Stellar wind stratification in the high-mass X-ray binary Vela X-1
• The VLT-FLAMES Tarantula Survey XXVI: Properties of the O-dwarf population in 30 Doradus
• No breakdown of the radiatively-driven wind theory in low-metallicity environments
• Modeling the early evolution of massive OB stars with an experimental wind routine
• Empirical mass-loss rates and clumping properties of Galactic early-type O supergiants
• Bondi-Hoyle-Lyttleton accretion in Supergiant X-ray binaries: stability and disk formation
• Simultaneous X-ray and optical spectroscopy of the Oef supergiant lambda Cep
• Spectroscopic evolution of massive stars on the main sequence
• Fast & slow winds from supergiants and Luminous Blue Variables
• Clumpy wind accretion in supergiant neutron star high mass X-ray binaries
• Interplay between pulsations and mass loss in the blue supergiant 55 Cygnus = HD 198478
• Global hot-star wind models for stars from Magellanic Clouds
• Stochastic light variations in hot stars from wind instability: Finding photometric signatures and testing against the TESS data
• Supergiant fast X-ray transients as an under-luminous class of supergiant X-ray binaries
• New mass-loss rates of B supergiants from global wind models
• The Shortest-period Wolf-Rayet binary in the Small Magellanic Cloud: Part of a high-order multiple system
• On the H$\alpha$ Behaviour of Blue Supergiants: Rise and Fall over the Bi-stability Jump
• X-ray, UV and optical analysis of supergiants: $\epsilon$ Ori
• The X-ray catalog of spectroscopically identified Galactic O stars: Investigating the dependence of X-ray luminosity on stellar and wind parameters
• Light variations due to the line-driven wind instability and wind blanketing in O stars
• Observational properties of massive black hole binary progenitors
• Upper Mass-Loss Limits and Clumping in the Intermediate and Outer Wind Regions of OB stars
• X-ray Observations of Bow Shocks around Runaway O Stars. The case of $\zeta$ Oph and BD+43${}^{\circ }$3654
• The Tarantula Massive Binary Monitoring V. R 144: a wind-eclipsing binary with a total mass > 140 Msun
• Stellar population of the superbubble N206 in the LMC I. Analysis of the Of-type stars
• Mass-loss rates of Very Massive Stars
• Wind inhibition by X-ray irradiation in HMXBs: the influence of clumping and the final X-ray luminosity
• Collective non-thermal emission from an extragalactic jet interacting with stars
• On the Origin of Wind Line Variability in O Stars
• Evolution of massive stars with new hydrodynamic wind models
• X-Shooting ULLYSES: Massive Stars at low metallicity IX: Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud
• e-MERLIN 21cm constraints on the mass-loss rates of OB stars in Cyg OB2
• Effect of scattering on the transonic solution topology and intrinsic variability of line-driven stellar winds
• X-ray diagnostics of massive star winds
• Mass loss and stellar superwinds
• Stellar wind models of central stars of planetary nebulae
• X-ray and optical spectroscopy of the massive young open cluster IC1805
• The Wolf-Rayet binaries of the nitrogen sequence in the Large Magellanic Cloud: spectroscopy, orbital analysis, formation, and evolution
• Optical spectroscopy of the blue supergiant Sk-69 279 and its circumstellar shell with SALT
• X-Shooting ULLYSES: Massive stars at low metallicity. IV. Spectral analysis methods and exemplary results for O stars
• Method and new tabulations for flux-weighted line-opacity and radiation line-force in supersonic media
• Empirical mass-loss rates and clumping properties of O-type stars in the LMC
• Evolution of rotating massive stars with new hydrodynamic wind models
• Evolution of rotating massive stars adopting a newer, self-consistent wind prescription at SMC metallicity
• New self-consistent wind parameters fitting optical spectra of O-type stars observed with HERMES spectrograph
• Influence of X-ray radiation on the hot star wind ionization state and on the radiative force
• Long-Wavelength, Free-Free Spectral Energy Distributions from Porous Stellar Winds
• Development of convective envelopes in massive stars: Implications for gravitational wave sources
• To clump or not to clump The impact of wind inhomogeneities on the optical and NIR spectroscopic analysis of massive OB stars
• X-Shooting ULLYSES: massive stars at low metallicity: XII. The clumped winds of O-type (super)giants in the Large Magellanic Cloud
• The nature of the light variability of magnetic Of?p star HD 191612
• Moving inhomogeneous envelopes of stars
• Low-metallicity massive single stars with rotation. III. Source of ionization and C-IV emission in I Zw 18
• Ultraviolet Spectropolarimetry with Polstar: Clumping and Mass-loss Rate Corrections
• Progress towards a 3D Monte Carlo radiative transfer code for outflow wind modelling
• Analytical Solutions for Radiation-Driven Winds in Massive Stars. I: The Fast Regime
• Supernova remnants in clumpy medium: A model of hydrodynamic and radio synchrotron evolution
• Evolution of stars with 60 and 200 Msun: predictions for WNh stars in the Milky Way
• Spherically symmetric model atmospheres using approximate lambda operators V. Static inhomogeneous atmospheres of hot dwarf stars
• The effect of horizontal plasma inhomogeneities in 3D NLTE radiation transfer in stellar atmospheres
• Current status of NLTE analysis of stellar atmospheres