On the ring nebulae around runaway Wolf-Rayet stars

Abstract

Wolf-Rayet stars are advanced evolutionary stages of massive stars. Despite their large mass-loss rates and high wind velocities, none of them display a bow shock, although a fraction of them are classified as runaway. Our 2.5-D numerical simulations of circumstellar matter around a 60Mo runaway star show that the fast Wolf-Rayet stellar wind is released into a wind-blown cavity filled with various shocks and discontinuities generated throughout the precedent evolutionary phases. The resulting fast-wind slow-wind interaction leads to the formation of spherical shells of swept-up dusty material similar to those observed in near infrared 24 micron with Spitzer, and which appear to be co-moving with the runaway massive stars, regardless of their proper motion and/or the properties of the local ambient medium. We interpret bright infrared rings around runaway Wolf-Rayet stars in the Galactic plane, like WR138a, as indication of their very high initial masses and a complex evolutionary history. Stellar-wind bow shocks become faint as stars run in diluted media, therefore, our results explain the absence of detected bow shocks around Galactic Wolf-Rayet stars such as the high-latitude, very fast-moving objects WR71, WR124 and WR148. Our results show that the absence of a bow shock is consistent with a runaway nature of some Wolf-Rayet stars. This questions the in-situ star formation scenario of high-latitude Wolf-Rayet stars in favor of dynamical ejection from birth sites in the Galactic plane.

arXiv comment6 pages, accepted to MNRAS

References in corpus (34)

• The chemical composition of the Sun
• Physical Properties of Wolf-Rayet Stars
• The PLUTO Code for Adaptive Mesh Computations in Astrophysical Fluid Dynamics
• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• Massive runaways and walkaway stars
• The Galactic WC stars: Stellar parameters from spectral analyses indicate a new evolutionary sequence
• The evolution of massive stars and their spectra I. A non-rotating 60 Msun star from the zero-age main sequence to the pre-supernova stage
• The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence
• Massive star evolution: Luminous Blue Variables as unexpected Supernova progenitors
• Revealing evolved massive stars with Spitzer
• Models of the circumstellar medium of evolving, massive runaway stars moving through the Galactic plane
• Multiple ring nebulae around blue supergiants
• Constraints on gamma-ray burst and supernova progenitors through circumstellar absorption lines
• Wind bubbles within H II regions around slowly moving stars
• Unlocking Galactic Wolf-Rayet stars with $\text{Gaia}$ DR2 I: Distances and absolute magnitudes
• Discovery of an OB Runaway Star Inside SNR S147
• Bow shock nebulae of hot massive stars in a magnetized medium
• A search for Ejecta Nebulae around Wolf-Rayet Stars using the SHS H$\alpha$ survey
• Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas
• Rotating Wolf-Rayet stars in a post RSG/LBV phase. An evolutionary channel towards long-duration GRBs?
• On the observability of bow shocks of Galactic runaway OB stars
• WISE morphological study of Wolf-Rayet nebulae
• Thermal emission from bow shocks I: 2D Hydrodynamic Models of the Bubble Nebula
• Wind nebulae and supernova remnants of very massive stars
• Can the magnetic field in the Orion arm inhibit the growth of instabilities in the bow shock of Betelgeuse?
• An ALMA 3mm continuum census of Westerlund 1
• Palomar/TripleSpec observations of {\it Spitzer}/MIPSGAL~24\mic\ circumstellar shells: unveiling the nature of their central sources
• The dynamics of the nebula M1-67 around the run-away Wolf-Rayet star WR 124
• On the stability of bow shocks generated by red supergiants: the case of IRC-10414
• Investigating Particle Acceleration in the Wolf-Rayet Bubble G2.4+1.4
• Characterizing Wolf-Rayet Stars in the Near and Mid Infrared
• Absence of hot gas within the Wolft-Rayet Bubble around WR16
• On the apparent absence of WR+NS systems: the curious case of WR124
• WR 148: Identifying the companion of an extreme runaway massive binary

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• Rectangular core-collapse supernova remnants: application to Puppis A
• On the bipolarity of Wolf-Rayet nebulae
• Mixing of materials in magnetised core-collapse supernova remnants
• Pulsar wind nebulae of runaway massive stars
• Ionization-Gasdynamic Simulations of Wind-Blown Nebulae around Massive Stars
• Modelling O-star astrospheres with different relative speeds between the ISM and the star: 2D and 3D MHD model comparison
• 3D mapping of the Wolf-Rayet nebula M1-67: clues for post-common envelope evolution in massive stars
• Discovery of an optical cocoon tail behind the runaway HD 185806
• Study of Wolf-Rayet stars using uGMRT