The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters

Abstract

Comprehensive spectral analyses of the Galactic Wolf-Rayet stars of the nitrogen sequence (i.e.\ the WN subclass) have been performed in a previous paper. However, the distances of these objects were poorly known. Distances have a direct impact on the "absolute" parameters, such as luminosities and mass-loss rates. The recent Gaia Data Release (DR2) of trigonometric parallaxes includes nearly all WN stars of our Galactic sample. In the present paper, we apply the new distances to the previously analyzed Galactic WN stars and rescale the results accordingly. On this basis, we present a revised catalog of 55 Galactic WN stars with their stellar and wind parameters. The correlations between mass-loss rate and luminosity show a large scatter, for the hydrogen-free WN stars as well as for those with detectable hydrogen. The slopes of the $\log L-\log \dot{M}$ correlations are shallower than found previously. The empirical Hertzsprung-Russell diagram (HRD) still shows the previously established dichotomy between the hydrogen-free early WN subtypes that are located on the hot side of the zero-age main sequence (ZAMS), and the late WN subtypes, which show hydrogen and reside mostly at cooler temperatures than the ZAMS (with few exceptions). However, with the new distances, the distribution of stellar luminosities became more continuous than obtained previously. The hydrogen-showing stars of late WN subtype are still found to be typically more luminous than the hydrogen-free early subtypes, but there is a range of luminosities where both subclasses overlap. The empirical HRD of the Galactic single WN stars is compared with recent evolutionary tracks. Neither these single-star evolutionary models nor binary scenarios can provide a fully satisfactory explanation for the parameters of these objects and their location in the HRD.

arXiv comment11 pages; accepted for publication in Astronomy & Astrophysics

References in corpus (37)

• The Gaia mission
• Correcting for the Effects of Interstellar Extinction
• Gaia Data Release 2: The astrometric solution
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• A new route towards merging massive black holes
• Gaia Data Release 2: Catalogue validation
• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
• Stellar evolution with rotation XI: Wolf-Rayet star populations at different metallicities
• On the role of continuum-driven eruptions in the evolution of very massive stars and Population III stars
• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• The empirical metallicity dependence of the mass-loss rate of O- and early B-type stars
• A catalogue of young runaway Hipparcos stars within 3kpc from the Sun
• Mass loss from late-type WN stars and its Z-dependence: very massive stars approaching the Eddington limit
• The Wolf-Rayet stars in the Large Magellanic Cloud: A comprehensive analysis of the WN class
• Stellar envelope inflation near the Eddington limit. Implications for the radii of Wolf-Rayet stars and luminous blue variables
• The Eddington factor as the key to understand the winds of the most massive stars. Evidence for a Gamma-dependence of Wolf-Rayet type mass loss
• Common envelope ejection in massive binary stars - Implications for the progenitors of GW150914 and GW151226
• The Galactic WC and WO stars: The impact of revised distances from Gaia DR2 and their role as massive black hole progenitors
• Wolf-Rayet stars in the Small Magellanic Cloud: I. Analysis of the single WN stars
• Stellar rotation: Evidence for a large horizontal turbulence and its effects on evolution
• Wolf-Rayet stars in the Small Magellanic Cloud: II. Analysis of the binaries
• The WR population predicted by massive single star and by massive binary evolution
• On the optically-thick winds of Wolf-Rayet stars
• The start of the Sagittarius spiral arm (Sagittarius origin) and the start of the Norma spiral arm (Norma origin) - model-computed and observed arm tangents at galactic longitudes -20 degrees < l < +23 degrees
• New X-ray Detections of WNL Stars
• The Shortest-period Wolf-Rayet binary in the Small Magellanic Cloud: Part of a high-order multiple system
• The Wolf-Rayet stars in M31: I. Analysis of the late-type WN stars
• Disentangling the Nature of the Radio Emission in Wolf Rayet Stars
• Phase-resolved XMM-Newton and swift observations of WR 25
• Polarization Light Curve Modeling of Corotating Interaction Regions in the Wind of the Wolf-Rayet Star WR 6
• An extensive spectroscopic time-series of three Wolf-Rayet stars. I. The lifetime of large-scale structures in the wind of WR 134
• On the apparent absence of WR+NS systems: the curious case of WR124
• Chandra Observations of WR147 Reveal a Double X-ray Source
• Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR2
• A 10-hour period revealed in optical spectra of the highly variable WN8 Wolf-Rayet star WR 123
• Revealing the Asymmetry of the Wind of the Variable Wolf-Rayet Star WR1 (HD4004) Through Spectropolarization

Cited by in corpus (81)

• On the nature of massive helium star winds and Wolf-Rayet-type mass loss
• Theory and Diagnostics of Hot Star Mass Loss
• Why binary interaction does not necessarily dominate the formation of Wolf-Rayet stars at low metallicity
• Unlocking Galactic Wolf-Rayet stars with $\text{Gaia}$ DR2 I: Distances and absolute magnitudes
• Driving classical Wolf-Rayet winds: A Γ- and Z-dependent mass-loss
• The Formation of a 70 Msun Black Hole at High Metallicity
• First 3D Radiation-Hydrodynamic Simulations of Wolf-Rayet Winds
• Gravitational wave sources in our Galactic backyard: Predictions for BHBH, BHNS and NSNS binaries detectable with LISA
• Massive star cluster origin for the galactic cosmic ray population at very-high energies
• The temperature dependency of Wolf-Rayet-type mass loss: An exploratory study for winds launched by the hot iron bump
• A massive helium star with a sufficiently strong magnetic field to form a magnetar
• Evolution of Wolf-Rayet stars as black hole progenitors
• A synthetic population of Wolf-Rayet stars in the LMC based on detailed single and binary star evolution models
• Unlocking Galactic Wolf-Rayet stars with $\text{Gaia}$ DR2 II: Cluster and Association membership
• Dynamically inflated wind models of classical Wolf-Rayet stars
• Evidence from high mass X-ray binaries that Galactic WR components of WR+O binaries end their life with a supernova explosion
• Line Luminosities of Galactic and Magellanic Cloud Wolf-Rayet stars
• Stripped-Envelope Stars in Different Metallicity Environments I. Evolutionary Phases, Classification and Populations
• Constraints on the contributions to the observed binary black hole population from individual evolutionary pathways in isolated binary evolution
• Red noise and pulsations in evolved massive stars
• Two Wolf-Rayet stars at the heart of colliding-wind binary Apep
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars: II. The northern WNE sequence
• X-ray properties of early-type stars in the Tarantula Nebula from T-ReX
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. III. The northern late-type nitrogen-rich sample
• The Wolf-Rayet binaries of the nitrogen sequence in the Large Magellanic Cloud: spectroscopy, orbital analysis, formation, and evolution
• The chaotic wind of WR 40 as probed by BRITE
• AU-scale radio imaging of the wind collision region in the brightest and most luminous non-thermal colliding wind binary Apep
• Exploring the influence of different velocity fields on Wolf-Rayet star spectra
• The nature of the companion in the Wolf-Rayet system EZ Canis Majoris
• The search for magnetic fields in two Wolf-Rayet stars and the discovery of a variable magnetic field in WR55
• Colliding stellar wind modelling of the X-ray emission from WR 140
• The Arches cluster revisited: IV. Observational constraints on the binary properties of very massive stars
• Investigating 39 Galactic Wolf-Rayet stars with VLTI/GRAVITY: Uncovering A Long Period Binary Desert
• Effects of Winds on the Optical Properties of Type Ib and Ic Supernova Progenitors
• Sagittarius B1 -- A Patchwork of H II Regions and PhotoDissociation Regions
• Unveiling the stellar origin of the Wolf-Rayet nebula NGC6888 through infrared observations
• The population synthesis of Wolf-Rayet stars involving binary merger channels
• A multi-wavelength search for intrinsic linear polarization in Wolf-Rayet winds
• New X-ray detections of known Wolf-Rayet stars
• Evidence for non-thermal X-ray emission from the double WR colliding-wind binary Apep
• Dust in the Wolf-Rayet Nebula M1-67
• Ups!... I did it again: unveiling the hidden companion in Upsilon Sagittarii, a unique binary system at a second mass transfer stage
• The formation and stability of a cold disc made out of stellar winds in the Galactic Centre
• A New Transition Wolf-Rayet WN/C Star in the Milky Way
• On the nature of the single eclipse per 80d orbit of the H-rich luminous WN star WR22
• Stellar-wind feedback and magnetic fields around young compact star clusters: 3D MHD simulations
• Surface chemical composition of single WNh stars
• Dust in RCW 58: clues to common envelope channel formation?
• Close binary evolution based on Gaia DR2: the origin of late WC-type Wolf-Rayet stars with low luminosity
• A Speckle-Imaging Search for Close and Very Faint Companions to the Nearest and Brightest Wolf-Rayet Stars
• 3D mapping of the Wolf-Rayet nebula M1-67: clues for post-common envelope evolution in massive stars
• Very massive stars at low metallicity: evolution, synthetic spectroscopy, and impact on the integrated light of starbursts
• Hydrogen-free Wolf-Rayet stars: Helium stars with envelope-inflation structure and rotation
• Possible Detection of X-Ray Emitting Circumstellar Material in the Synchrotron-Dominated Supernova Remnant RX J 1713.7-3946
• MEGARA-GTC Stellar Spectral Library (II). MEGASTAR First Release
• Multiple variability time-scales of the early nitrogen-rich Wolf-Rayet star WR7
• The non-thermal emission from the colliding-wind binary Apep
• Radio Variability from Co-Rotating Interaction Regions Threading Wolf-Rayet Winds
• Constraints on Clumps in the Representative Wind of the WN8 Wolf-Rayet star HD96548 = WR40 with Simultaneous Broadband Light and Linear-Polarisation Variability
• Unraveling the nature of a deeply embedded Wolf-Rayet star WR 121a
• A global view on the colliding-wind binary WR 147
• Detection of diffuse gamma-ray emission towards a massive star forming region hosting Wolf-Rayet stars
• Metal-poor single Wolf-Rayet stars: The interplay of optically thick winds and rotation
• Eternal homogeneous gravitational collapse: A comprehensive analysis from $\Theta$ parametrization
• A constant upper luminosity limit of cool supergiant stars down to the extremely low metallicity of I Zw 18
• The magnetic, spectroscopic, and photometric variability of the Wolf-Rayet star WR55
• Astrophysical implications of an eternal homogeneous gravitational collapse model with a parametrization of expansion scalar
• Evolution of stars with 60 and 200 Msun: predictions for WNh stars in the Milky Way
• Chandra revisits WR48a: testing colliding wind models in massive binaries
• EWOCS-IV: 1Ms ACIS Chandra observation of the supergiant B[e] star Wd1-9
• Spatial distribution and clustering properties of the young stellar populations in the Carina Nebula complex and Car OB1
• Dynamically consistent analysis of Galactic WN4b stars
• The origin of the very-high-energy radiation along the jet of Centaurus A
• The detectability of Wolf-Rayet Stars in M33-ike spirals up to 30 Mpc
• Adiabatic Mass Loss In Binary Stars. VI. Massive Helium Binary Stars
• Discovery of a 310-day Period from the Enshrouded Massive System NaSt1 (WR 122)
• X-ray and radio data obtained by XMM-Newton and VLA constrain the stellar wind of the magnetic quasi-Wolf-Rayet star in HD45166
• ALMA measurements of mass loss and wind clumping in the massive stars of the Arches cluster
• 4D Grid-fitting of UV-optical spectra of massive stars. I. Numerical technique and its associated uncertainties
• Impact of Massive Binary Star and Cosmic Evolution on Gravitational Wave Observations II: Double Compact Object Rates and Properties
• Deciphering the gamma-ray emission in the Cygnus region