On the stability of bow shocks generated by red supergiants: the case of IRC-10414

Abstract

In this Letter, we explore the hypothesis that the smooth appearance of bow shocks around some red supergiants (RSGs) might be caused by the ionization of their winds by external sources of radiation. Our numerical simulations of the bow shock generated by IRC-10414 (the first-ever RSG with an optically detected bow shock) show that the ionization of the wind results in its acceleration by a factor of two, which reduces the difference between the wind and space velocities of the star and makes the contact discontinuity of the bow shock stable for a range of stellar space velocities and mass-loss rates. Our best fit model reproduces the overall shape and surface brightness of the observed bow shock and suggests that the space velocity and mass-loss rate of IRC-10414 are $\approx$50 $\mathrm{km}{\mathrm{s}}^{-1}$ and $\approx$$10^{-6}$ $M_{\odot }{\mathrm{yr}}^{-1}$, respectively, and that the number density of the local ISM is $\approx$3 ${\mathrm{cm}}^{-3}$. It also shows that the bow shock emission comes mainly from the shocked stellar wind. This naturally explains the enhanced nitrogen abundance in the line-emitting material, derived from the spectroscopy of the bow shock. We found that photoionized bow shocks are $\approx$15$-$50 times brighter in optical line emission than their neutral counterparts, from which we conclude that the bow shock of IRC-10414 must be photoionized.

5 pages, 5 figures. Accepted for publication in MNRAS Letters

References in corpus (4)

• PLUTO: a Numerical Code for Computational Astrophysics
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• The dust condensation sequence in red super-giant stars
• The enigmatic nature of the circumstellar envelope and bow shock surrounding Betelgeuse as revealed by Herschel. I. Evidence of clumps, multiple arcs, and a linear bar-like structure

Cited by in corpus (19)

• Models of the circumstellar medium of evolving, massive runaway stars moving through the Galactic plane
• Interacting supernovae from photoionization-confined shells around red supergiant stars
• Asymmetric supernova remnants generated by Galactic, massive runaway stars
• Bow shock nebulae of hot massive stars in a magnetized medium
• On the observability of bow shocks of Galactic runaway OB stars
• Wind nebulae and supernova remnants of very massive stars
• Dynamical friction for supersonic motion in a homogeneous gaseous medium
• 3D MHD astrospheres: applications to IRC-10414 and Betelgeuse
• Modelling interstellar structures around Vela X-1
• Non-thermal radio supernova remnants of exiled Wolf-Rayet stars
• Modelling multi-wavelength observational characteristics of bow shocks from runaway early type stars
• The Secret Lives of Cepheids: Evolution, Mass Loss, and Ultraviolet Emission of the Long-Period Classical Cepheid $l$ Carinae
• On the ring nebulae around runaway Wolf-Rayet stars
• Modeling the cometary structure of the planetary nebula HFG1 based on the evolution of its binary central star V664 Cas
• Production of secondary particles in heavy nuclei interactions in supernova remnants
• Cold gas in hot star clusters: the wind from the red supergiant W26 in Westerlund 1
• How does the stellar wind influence the radio morphology of a supernova remnant?
• Stabilization of the astropause by periodic fluctuations of the stellar wind
• Using numerical models of bow shocks to investigate the circumstellar medium of massive stars