The population synthesis of Wolf-Rayet stars involving binary merger channels

Abstract

Wolf-Rayet stars (WRs) are very important massive stars. However, their origin and the observed binary fraction within the entire WR population are still debated. We investigate some possible merger channels for the formation of WRs, including main sequence (MS)/ Hertzsprung Gap (HG) + MS, He + HG/ Giant Branch (GB). We find that many products produced via binary merger can evolve into WRs, the MS/ HG + MS merger channel can explain WRs with luminosities higher than $\sim 10^{5.4}$\,L${}_{\odot }$, while the He + HG/ GB merger channel can explain low-luminosity WRs in the range of $10^{4.7}$\,L${}_{\odot }$\,$\sim$\,$10^{5.5}$\,L${}_{\odot }$. In the population synthesis analysis of WRs, we assume an initial binary fraction ($f_{\mathrm{ini},\mathrm{bin}}$) of 50\% and 100\% for massive stars. We also assume that MS/ HG + MS merger products are non-rotating or rapidly rotating ($\omega /{\omega }_{\mathrm{crit}}=0.8$). In different cases, the calculated single fractions of WRs range from $22.2\%$ to $60.6\%$ in the Milky Way (MW) and from $8.3\%$ to $70.9\%$ in the Large Magellanic Cloud (LMC). The current observations fall within the range of our calculations. When the merger product of MS/HG+MS rotates rapidly, we estimate that there are approximately 1015 to 1396 WRs in the MW and 128 to 204 WRs in the LMC. Our model also roughly reproduces the observed single-peak luminosity distribution of WRs in the MW. However, the weak bimodal luminosity distribution observed in the LMC is not reproduced in our model. We assess that this may be due to the model underestimating the mass-loss rate in the LMC. In conclusion, we consider that the binary merger is significant formation channel for WR formation, and can explain the observed high fraction of the single WRs in the total population.

arXiv comment14 pages, 8 figures , Accepted to APJ

References in corpus (78)

• On the variation of the Initial Mass Function
• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• How Massive Single Stars End their Life
• Binary interaction dominates the evolution of massive stars
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• Evolution of binary stars and the effect of tides on binary populations
• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• 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)
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• Common Envelope Evolution: Where we stand and how we can move forward
• Presupernova Evolution of Rotating Massive Stars I: Numerical Method and Evolution of the Internal Stellar Structure
• Physical Properties of Wolf-Rayet Stars
• Pre-Supernova Evolution of Massive Single and Binary Stars
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• Double Compact Objects I: The Significance Of The Common Envelope On Merger Rates
• Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
• The VLT-FLAMES Tarantula Survey VIII. Multiplicity properties of the O-type star population
• Stellar evolution with rotation XI: Wolf-Rayet star populations at different metallicities
• Single star progenitors of long gamma-ray bursts I: Model grids and redshift dependent GRB rate
• Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity
• The Star Formation History of the Large Magellanic Cloud
• The Discordance of Mass-Loss Estimates for Galactic O-Type Stars
• The incidence of stellar mergers and mass gainers among massive stars
• Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies
• Merging black hole binaries: the effects of progenitor's metallicity, mass-loss rate and Eddington factor
• Formation of contact in massive close binaries
• Grids of stellar models with rotation II. WR populations and supernovae/GRB progenitors at Z = 0.014
• 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
• Evolution and fate of very massive stars
• The VLT-FLAMES Tarantula Survey XII. Rotational velocities of the single O-type stars
• The mass-loss rates of red supergiants and the de Jager prescription
• Forming short-period Wolf-Rayet X-ray binaries and double black holes through stable mass transfer
• The Wolf-Rayet stars in the Large Magellanic Cloud: A comprehensive analysis of the WN class
• On the Binding Energy Parameter $\lambda$ of Common Envelope Evolution
• A new mass-loss rate prescription for red supergiants
• Stellar and Wind Properties of LMC WC4 stars - A metallicity dependence for Wolf-Rayet mass-loss rates
• Stellar envelope inflation near the Eddington limit. Implications for the radii of Wolf-Rayet stars and luminous blue variables
• Stellar Collisions and the Interior Structure of Blue Stragglers
• Modelling the binary progenitor of supernova 1993J
• Binary Merger Progenitors for Gamma-Ray Bursts and Hypernovae
• Rejuvenation of stellar mergers and the origin of magnetic fields in massive stars
• Thermal Timescale Mass Transfer and the Evolution of White Dwarf 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 Galactic WC and WO stars: The impact of revised distances from Gaia DR2 and their role as massive black hole progenitors
• Towards a better understanding of the evolution of Wolf-Rayet stars and Type Ib/Ic supernova progenitors
• The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters
• Structure and evolution of high-mass stellar mergers
• Populating the Galaxy with low-mass X-ray binaries
• Binary Population Synthesis
• A Spectroscopic Survey of WNL Stars in the LMC: General Properties and Binary Status
• The VLT-FLAMES Tarantula Survey XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus
• The VLT-FLAMES Tarantula Survey XXI. Stellar spin rates of O-type spectroscopic binaries
• A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds: First Results
• A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds. IV. A Final Census
• Grids of stellar models with rotation VI: Models from 0.8 to 120 $M_{\odot }$ at a metallicity Z = 0.006
• Formation of black holes in the pair-instability mass gap: evolution of a post-collision star
• Population Synthesis for Symbiotic X-ray Binaries
• Mixing in massive stellar mergers
• Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars
• White-dwarf red-giant mergers, early-type R stars, J stars and lithium
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. I. The northern WC sequence
• The Close Binary Frequency of Wolf-Rayet Stars as a Function of Metallicity in M31 and M33
• A synthetic population of Wolf-Rayet stars in the LMC based on detailed single and binary star evolution models
• Stripped-Envelope Stars in Different Metallicity Environments I. Evolutionary Phases, Classification and Populations
• SNAPSHOT: Connections between Internal and Surface Properties of Massive Stars
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars: II. The northern WNE sequence
• Effects of Irradiation on the Evolution of Ultra-compact X-ray Binaries
• Formation of black widows through ultra-compact X-ray binaries with He star companions
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. III. The northern late-type nitrogen-rich sample
• Formation and Destiny of White Dwarf and Be Star Binaries
• The impact of convective criteria on the properties of massive stars
• The formation of subdwarf A-type stars
• A Study of Wolf-Rayet stars Formed via Chemically Homogeneous Evolution
• Hydrogen-free Wolf-Rayet stars: Helium stars with envelope-inflation structure and rotation

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• Investigating 39 Galactic Wolf-Rayet stars with VLTI/GRAVITY: Uncovering A Long Period Binary Desert
• A possible formation scenario of the Gaia ID 3425577610762832384: inner binary merger inside a triple common envelope
• Stellar evolution through the Red Supergiant phase
• Adiabatic Mass Loss In Binary Stars. VI. Massive Helium Binary Stars
• Kinematics of Wolf-Rayet Stars in the LMC: Clues to Subtype Origins
• The mixing of internal gravity waves and lithium production in intermediate-mass AGB stars