Measuring mass-loss rates and constraining shock physics using X-ray line profiles of O stars from the Chandra archive

Abstract

We quantitatively investigate the extent of wind absorption signatures in the X-ray grating spectra of all non-magnetic, effectively single O stars in the Chandra archive via line profile fitting. Under the usual assumption of a spherically symmetric wind with embedded shocks, we confirm previous claims that some objects show little or no wind absorption. However, many other objects do show asymmetric and blue shifted line profiles, indicative of wind absorption. For these stars, we are able to derive wind mass-loss rates from the ensemble of line profiles, and find values lower by an average factor of 3 than those predicted by current theoretical models, and consistent with H-alpha if clumping factors of f_cl ~ 20 are assumed. The same profile fitting indicates an onset radius of X-rays typically at r ~ 1.5 R_star, and terminal velocities for the X-ray emitting wind component that are consistent with that of the bulk wind. We explore the likelihood that the stars in the sample that do not show significant wind absorption signatures in their line profiles have at least some X-ray emission that arises from colliding wind shocks with a close binary companion. The one clear exception is zeta Oph, a weak-wind star that appears to simply have a very low mass-loss rate. We also reanalyse the results from the canonical O supergiant zeta Pup, using a solar-metallicity wind opacity model and find Mdot = 1.8 \times 10^{-6} M_sun/yr, consistent with recent multi-wavelength determinations.

18 pages; 8 figures; 4 tables; Monthly Notices of the Royal Astronomical Society, in press

References in corpus (58)

• The chemical composition of the Sun
• A new calibration of stellar parameters of Galactic O stars
• A Grid of NLTE Line-Blanketed Model Atmospheres of O-type Stars
• Mass loss from hot massive stars
• The Discordance of Mass-Loss Estimates for Galactic O-Type Stars
• On the origin of the O and B-type stars with high velocities II Runaway stars and pulsars ejected from the nearby young stellar groups
• The Chandra High Energy Transmission Grating: Design, Fabrication, Ground Calibration and Five Years in Flight
• 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
• Low mass loss rates in O-type stars: Spectral signatures of dense clumps in the wind of two Galactic O4 stars
• A Magnetic Confinement vs. Rotation Classification of Massive-Star Magnetospheres
• Neglecting the porosity of hot-star winds can lead to underestimating mass-loss rates
• High resolution X-Ray spectroscopy of Zeta Puppis with the XMM-Newton Reflection Grating Spectrometer
• Properties of Galactic early-type O-supergiants: A combined FUV-UV and optical analysis
• Quantitative studies of the optical and UV spectra of Galactic early B supergiants I. Fundamental parameters
• The Effect of Porosity on X-ray Emission Line Profiles from Hot-Star Winds
• L-band spectroscopy of Galactic OB-stars
• An Introduction to the Chandra Carina Complex Project
• Spectral analysis of early-type stars using a genetic algorithm based fitting method
• Mass loss from inhomogeneous hot star winds II. Constraints from a combined optical/UV study
• High resolution X-ray spectroscopy of bright O type stars
• Mass loss from inhomogeneous hot star winds I. Resonance line formation in 2D models
• Detection of Doppler Shifted X-ray Line Profiles from the Wind of Zeta Puppis (O4f)
• Analysis of Galactic late-type O dwarfs: more constraints on the weak wind problem
• X-Ray Line Profiles from Parameterized Emission Within an Accelerating Stellar Wind
• Clumping in the inner winds of hot, massive stars from hydrodynamical line-driven instability simulations
• 3D models of radiatively driven colliding winds in massive O+O star binaries - III. Thermal X-ray emission
• Carina OB Stars: X-ray Signatures of Wind Shocks and Magnetic Fields
• 2D Simulations of the Line-Driven Instability in Hot-Star Winds: II. Approximations for the 2D Radiation Force
• 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
• X-ray Emission Line Profile Modeling of O stars: Fitting a Spherically-Symmetric Analytic Wind-Shock Model to the Chandra Spectrum of zeta Puppis
• Measurements and analysis of helium-like triplet ratios in the X-ray spectra of O-type stars
• On the Weak-Wind Problem in Massive Stars: X-ray Spectra Reveal a Massive Hot Wind in μ Columbae
• Wind signatures in the X-ray emission line profiles of the late O supergiant $\zeta$ Orionis
• A mass-loss rate determination for zeta Puppis from the quantitative analysis of X-ray emission line profiles
• First Application of the Fe XVII I(17.10 A)/I(17.05 A) Line Ratio to Constrain the Plasma Density of a Cosmic X-ray Source
• The Spectral Evolution along the Z track of the Bright Neutron Star X-ray Binary GX 17+2
• Evidence for a physically bound third component in HD 150136
• X-Rays From Massive OB Stars: Thermal Emission From Radiative Shocks
• High-Resolution Chandra X-ray Imaging and Spectroscopy of the Sigma Orionis Cluster
• Chandra X-ray spectroscopy of the very early O supergiant HD 93129A: constraints on wind shocks and the mass-loss rate
• Chandra spectroscopy of the hot star beta Crucis and the discovery of a pre-main-sequence companion
• A generalised porosity formalism for isotropic and anisotropic effective opacity and its effects on X-ray line attenuation in clumped O star winds
• A detailed X-ray investigation of ζ Puppis III. A spectral analysis of the whole RGS spectrum
• The non-thermal radio emitter HD 93250 resolved by long baseline interferometry
• Constraints on porosity and mass loss in O-star winds from modeling of X-ray emission line profile shapes
• Probing the wind-wind collision in Gamma Velorum with high-resolution Chandra X-ray spectroscopy: evidence for sudden radiative braking and non-equilibrium ionization
• Theoretical X-ray Line Profiles from Colliding Wind Binaries
• Modeling broadband X-ray absorption of massive star winds
• Chandra X-ray Observations of the Young Stellar Cluster NGC 6193 in the Ara OB1 Association
• Three-dimensional orbits of the triple-O stellar system HD 150136
• Evidence for the importance of resonance scattering in X-ray emission line profiles of the O star $\zeta$ Puppis
• The Correlation between X-Ray Line Ionization and Optical Spectral Types of the OB Stars
• High Resolution X-ray Spectra of the Brightest OB Stars in the Cygnus OB2 Association
• The Nearest Star of spectral type O3: A Component of the Multiple System HD 150136
• Global modelling of X-ray spectra produced in O-type star winds
• Hot and cool: two emission-line stars with constrasting behaviours in the same XMM-Newton field
• X-Atlas: An Online Archive of Chandra's Stellar High Energy Transmission Gratings Observations
• Nonlinear Evolution of the Radiation-Driven Magneto-Acoustic Instability (RMI)

Cited by in corpus (60)

• A coordinated X-ray and Optical Campaign of the Nearest Massive Eclipsing Binary, $\delta$ Orionis Aa: IV. A multiwavelength, non-LTE spectroscopic analysis
• 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
• Magnetic massive stars as progenitors of "heavy" stellar-mass black holes
• 2D wind clumping in hot, massive stars from hydrodynamical line-driven instability simulations using a pseudo-planar approach
• 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
• The Chandra Planetary Nebulae Survey (ChanPlaNS): III. X-ray Emission from the Central Stars of Planetary Nebulae
• 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
• Empirical mass-loss rates and clumping properties of Galactic early-type O supergiants
• Simultaneous X-ray and optical spectroscopy of the Oef supergiant lambda Cep
• Spectroscopic evolution of massive stars on the main sequence
• Global hot-star wind models for stars from Magellanic Clouds
• New mass-loss rates of B supergiants from global wind models
• X-ray, UV and optical analysis of supergiants: $\epsilon$ Ori
• CMF models of hot star winds II. Reduction of O star wind mass-loss rates in global models
• Characterizing the turbulent porosity of stellar-wind structure generated by the line-deshadowing instability
• Measuring the shock-heating rate in the winds of O stars using X-ray line spectra
• Bow shocks, bow waves, and dust waves. I. Strong coupling limit
• 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
• Probing Wolf-Rayet Winds: Chandra/HETG X-Ray Spectra of WR 6
• Wind properties of Milky Way and SMC massive stars: empirical Z dependence from CMFGEN models
• On the Origin of Wind Line Variability in O Stars
• Spectroscopic evolution of massive stars near the main sequence at low metallicity
• Mass loss and stellar superwinds
• e-MERLIN 21cm constraints on the mass-loss rates of OB stars in Cyg OB2
• X-ray diagnostics of massive star winds
• Effect of scattering on the transonic solution topology and intrinsic variability of line-driven stellar winds
• Investigating episodic mass loss in evolved massive stars: I. Spectroscopy of dusty massive stars in ten southern galaxies
• Atmospheric NLTE-Models for the Spectroscopic Analysis of Blue Stars with Winds. III. X-ray emission from wind-embedded shocks
• 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
• Carbon line formation and spectroscopy in O-type stars
• Chandra grating spectroscopy of embedded wind shock X-ray emission from O stars shows low plasma temperatures and significant wind absorption
• A Deep Exposure in High Resolution X-Rays Reveals the Hottest Plasma in the $\zeta$Puppis Wind
• Physics of mass loss in massive stars
• Using Shell Models to Investigate Clumping in the Wind of the O7Iaf+ Supergiant AzV83
• Coordinated UV and X-ray spectroscopic observations of the O-type giant xi Per: the connection between X-rays and large-scale wind structure
• Modeling X-ray Emission Line Profiles from Massive Star Winds - A Review
• X-ray emission of massive stars and their winds
• Follow-up observations of X-ray emitting hot subdwarf star: the He-rich sdO BD +37° 1977
• Chandra spectral measurements of the O supergiant $\zeta$ Puppis indicate a surprising increase in the wind mass-loss rate over 18 years
• A Coordinated X-ray and Optical Campaign on the Nearest Massive Eclipsing Binary, Delta Ori Aa: I. Overview of the X-ray Spectrum
• Solving the gamma-ray radiative transfer equation for supernovae
• Creating and using large grids of precalculated model atmospheres for a rapid analysis of stellar spectra
• A Time-Dependent Spectral Analysis of $\gamma$ Cassiopeiae
• The First Candidate Colliding-Wind Binary in M33
• Helium-like X-ray line complexes show that the hottest plasma on the O supergiant zeta Puppis is in its wind
• Investigating episodic mass loss in evolved massive stars: III. Spectroscopy of dusty massive stars in three northern galaxies
• Testing the Reliability of X-rays as a Tool for Constraining Mass-loss Rates of Hot Stars
• The mass discrepancy problem in O stars of solar metallicity. Does it still exist?
• Observed epochal variations in X-ray lines from the O Supergiant $\zeta$ Puppis do not require substantial changes in the wind mass flux
• Follow-up observations of X-ray emitting hot subdwarf stars: the compact He-poor sdO star Feige 34
• Sub-photospheric fluctuations in magnetized radiative envelopes: contribution from unstable magnetosonic waves
• Winds of Massive Stars: High Resolution X-ray Spectra of Stars in NGC 3603
• Perspectives for observing hot massive stars with XMM-Newton in the years 2017 -- 2027
• Deriving X-ray Line Profiles for Massive-Star Winds from Momentum-Conserving Dynamical Working Surface Solutions
• X-ray diagnostics of massive star winds