Can the magnetic field in the Orion arm inhibit the growth of instabilities in the bow shock of Betelgeuse?

Marle, Allard Jan van; Decin, L.; Méliani, Z.

doi:10.1051/0004-6361/201321968

Cited by 37 publications

(27 citation statements)

References 31 publications

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“…A photoionized bow shock may therefore fit the observations better than a neutral one. The ISM magnetic field may also be able to suppress instabilities sufficiently to agree with observations 37 . The multiple arcs may be a projection effect from undulations in the shock surface; whatever the correct explanation, there is no indication that this arc-shaped structure is anything other than a bow shock.…”

Section: Radiation-hydrodynamics Simulationssupporting

confidence: 66%

Interacting supernovae from photoionization-confined shells around red supergiant stars

Mackey¹,

Mohamed

Gvaramadze

et al. 2014

Nature

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Betelgeuse, a nearby red supergiant, is a runaway star with a powerful stellar wind that drives a bow shock into its surroundings 1-4 . This picture has been challenged by the discovery of a dense and almost static shell 5 that is three times closer to the star than the bow shock and has been decelerated by some external force. The two physically distinct structures cannot both be formed by the hydrodynamic interaction of the wind with the interstellar medium. Here we report that a model in which Betelgeuse's wind is photoionized by radiation from external sources can explain the static shell without requiring a new understanding of the bow shock. Pressure from the photoionized wind generates a standing shock in the neutral part of the wind 6 and forms an almost static, photoionization-confined shell. Other red supergiants should have significantly more massive shells than Betelgeuse, because the photoionization-confined shell traps up to 35 per cent of all mass lost during the red supergiant phase, confining this gas close to the star until it explodes. After the supernova explosion, massive shells dramatically affect the supernova lightcurve, providing a natural explanation for the many supernovae that have signatures of circumstellar interaction.Red supergiants are massive stars near the end of their lives, and are direct progenitors of core-collapse supernovae 7, 8 . They evolve from O-and B-type stars (hot, luminous sources of ionizing photons), and so these stars are often found together, within or near star clusters 9 . As a result, the cool stellar winds of red supergiants are often photoionized by external radiation fields [10][11][12][13] . To calculate the radiation hydrodynamics of a photoionized red supergiant wind, we simplify the problem by assuming spherical symmetry. We use an approximate two-temperature equation of state for the gas, for which both the neutral and photoionized gases are isothermal with 1 temperatures T = T n and T i ≫ T n , respectively. The ionized and neutral isothermal sound speeds similarly satisfy a i ≫ a n . The photoionized part of the red supergiant wind is accelerated as a result of ionization heating 14 , whereas the neutral part is decelerated 6 if the wind speed through the ionization front, v n , satisfies v n ≤ 2a i .The resulting flow is depicted in Fig. 1. The outermost layer is the interface where the wind meets the interstellar medium. For static stars this is a spherical, detached shell, and for stars moving supersonically it is a bow shock. A photoionization-confined shell -a dense, shocked layer separating the neutral inner wind from the ionized outer wind -forms closer to the star. We identify this with the recently-discovered shell in Betelgeuse's circumstellar medium 5 .The properties of the photoionization-confined shell are calculated analytically and verified with simulations in Methods. Its outer boundary, R IF , is calculated following previous work 10 (Extended Data Fig. 1), and the standing shock radius, R shell , is obtained by requiring pressur...

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Section: Radiation-hydrodynamics Simulationssupporting

confidence: 66%

Interacting supernovae from photoionization-confined shells around red supergiant stars

Mackey¹,

Mohamed

Gvaramadze

et al. 2014

Nature

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“…whereṀ denotes the time-dependent mass-loss rate of the massive star, r is the distance to the origin of the domain, O, and vw is the wind velocity. The same method has been used in Comerón & Kaper (1998) and van Marle et al (2007van Marle et al ( , 2011van Marle et al ( , 2014. The stellar wind parameters ρw and vw are time-dependently interpolated from the tabulated stellar evolution model of a non-rotating 60 M star presented in Groh et al (2014).…”

Section: Simulation Methods For the Pre-supernova Phasementioning

confidence: 99%

Wind nebulae and supernova remnants of very massive stars

Meyer

Петров

Pohl

2020

Monthly Notices of the Royal Astronomical Society

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A very small fraction of (runaway) massive stars have masses exceeding 60-70 M and are predicted to evolve as Luminous-Blue-Variable and Wolf-Rayet stars before ending their lives as core-collapse supernovae. Our 2D axisymmetric hydrodynamical simulations explore how a fast wind (2000 km s −1 ) and high mass-loss rate (10 −5 M yr −1 ) can impact the morphology of the circumstellar medium. It is shaped as 100 pc-scale wind nebula which can be pierced by the driving star when it supersonically moves with velocity 20-40 km s −1 through the interstellar medium (ISM) in the Galactic plane. The motion of such runaway stars displaces the position of the supernova explosion out of their bow shock nebula, imposing asymmetries to the eventual shock wave expansion and engendering Cygnus-loop-like supernova remnants. We conclude that the size (up to more than 200 pc) of the filamentary wind cavity in which the chemically enriched supernova ejecta expand, mixing efficiently the wind and ISM materials by at least 10% in number density, can be used as a tracer of the runaway nature of the very massive progenitors of such 0.1 Myr old remnants. Our results motivate further observational campaigns devoted to the bow shock of the very massive stars BD+43 3654 and to the close surroundings of the synchrotron-emitting Wolf-Rayet shell G2.4+1.4.

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“…The set of phenomena associated with IS magnetic field listed below was discovered during a number of numerical modelling of the SW vs ISM interactions. In our paper, we pay attention to HD and MHD models presented by van Marle et al (2014) and Meyer et al (2017). These models included or excluded the magnetic field of the ISM.…”

Section: Phenomena Associated With Interstellar Magnetic Fieldmentioning

confidence: 99%

“…Its image reminds one of smooth shocks around other stars like UU Aur and X Pav (Cox et al , 2012). The main goal of the study of van Marle et al (2014) was to explain the lack of instabilities by the presence of an IS magnetic field as an alternative theory – that the growth of instabilities is inhibited by an IS magnetic field. IS magnetic fields are typically weak, but can stretch over long distances.…”

Section: Phenomena Associated With Interstellar Magnetic Fieldmentioning

confidence: 99%

Interstellar medium magnetic field in bow shock modelling

Kotlarz

Ratkiewicz

Konior

2018

AEAT

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Purpose This paper aims to demonstrate the impact of interstellar (IS) magnetic field on stellar shocks existence, shape and size in the stellar wind (SW) vs interstellar medium (ISM) numerical models. Design/methodology/approach Comparison of hydrodynamics (HD) and magnetohydrodynamic (MHD) models results with or without ISM magnetic field, its intensity and ISM parameters. Findings ISM magnetic field facilitates formation and stabilises bow shocks around all astrophysical objects. ISM magnetic field may also be one of the reasons for a bow shock existence around the Sun. Practical implications ISM magnetic field should be implemented in MHD and future kinetic numerical models of the SW interaction with ISM plasma. Originality/value This paper presents the results of HD and MHD models of bow shocks and the importance of ISM magnetic field implementation, according to astronomical bow shock observations. The study also presents a review of the most important papers showing the numerical results of bow shock formation.

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Can the magnetic field in the Orion arm inhibit the growth of instabilities in the bow shock of Betelgeuse?

Cited by 37 publications

References 31 publications

Interacting supernovae from photoionization-confined shells around red supergiant stars

Interacting supernovae from photoionization-confined shells around red supergiant stars

Wind nebulae and supernova remnants of very massive stars

Interstellar medium magnetic field in bow shock modelling

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