Wolf-Rayet stars in the Small Magellanic Cloud: I. Analysis of the single WN stars

Abstract

Wolf-Rayet (WR) stars have a severe impact on their environments owing to their strong ionizing radiation fields and powerful stellar winds. Since these winds are considered to be driven by radiation pressure, it is theoretically expected that the degree of the wind mass-loss depends on the initial metallicity of WR stars. Following our comprehensive studies of WR stars in the Milky Way, M31, and the LMC, we derive stellar parameters and mass-loss rates for all seven putatively single WN stars known in the SMC. Based on these data, we discuss the impact of a low-metallicity environment on the mass loss and evolution of WR stars. The quantitative analysis of the WN stars is performed with the Potsdam Wolf-Rayet (PoWR) model atmosphere code. The physical properties of our program stars are obtained from fitting synthetic spectra to multi-band observations. In all SMC WN stars, a considerable surface hydrogen abundance is detectable. The majority of these objects have stellar temperatures exceeding 75 kK, while their luminosities range from 10^5.5 to 10^6.1 Lsun. The WN stars in the SMC exhibit on average lower mass-loss rates and weaker winds than their counterparts in the Milky Way, M31, and the LMC. By comparing the mass-loss rates derived for WN stars in different Local Group galaxies, we conclude that a clear dependence of the wind mass-loss on the initial metallicity is evident, supporting the current paradigm that WR winds are driven by radiation. A metallicity effect on the evolution of massive stars is obvious from the HRD positions of the SMC WN stars at high temperatures and high luminosities. Standard evolution tracks are not able to reproduce these parameters and the observed surface hydrogen abundances. Homogeneous evolution might provide a better explanation for their evolutionary past.

arXiv comment18+12 pages; 22+8 figures; accepted for publication in A&A

References in corpus (66)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The chemical composition of the Sun
• The USNO-B Catalog
• Mass-loss predictions for O and B stars as a function of metallicity
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• Pre-Supernova Evolution of Massive Single and Binary Stars
• The Progenitor Stars of Gamma-Ray Bursts
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• Mass loss from hot massive stars
• Evolution of rapidly rotating metal-poor massive stars towards gamma-ray bursts
• The rotation rates of massive stars: the role of binary interaction through tides, mass transfer and mergers
• Stellar evolution with rotation XI: Wolf-Rayet star populations at different metallicities
• The effect of massive binaries on stellar populations and supernova progenitors
• Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity
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• The Magellanic Clouds Photometric Survey: The Small Magellanic Cloud Stellar Catalog and Extinction Map
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• Bump Cepheids in the Magellanic Clouds: Metallicities, the Distances to the LMC and SMC, and the Pulsation-Evolution Mass Discrepancy
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• A cosmic abundance standard: chemical homogeneity of the solar neighbourhood and the ISM dust-phase composition
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• Chemical Cartography with APOGEE: Large-scale Mean Metallicity Maps of the Milky Way
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• Spitzer SAGE-SMC Infrared Photometry of Massive Stars in the Small Magellanic Cloud
• The evolution of rotating very massive stars with LMC composition
• Reduced Wolf-Rayet Line Luminosities at Low Metallicity
• On the consistent treatment of the quasi-hydrostatic layers in hot star atmospheres
• The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence
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• A Search for Wolf-Rayet Stars in the Small Magellanic Cloud
• Massive star formation in Wolf-Rayet galaxies. III: Analysis of the O and WR populations
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• Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas
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• Abell 48 - a rare WN-type central star of a planetary nebula
• The Wolf-Rayet stars in M31: I. Analysis of the late-type WN stars
• Another single hydrogen-rich Wolf-Rayet star in the SMC?

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