Interacting supernovae from photoionization-confined shells around red supergiant stars

Mackey, Jonathan; Mohamed, S.; Gvaramadze, V. V.; Kotak, R.; Langer, N.; Meyer, Dominique M.-A.; Moriya, Takashi J.; Neilson, Hilding R.

doi:10.1038/nature13522

Cited by 69 publications

(86 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Externallyphotoionized cool runaway stars that move rapidly in the H II region produced by an other source of ionizing radiation have particularly bright optical emission, see e.g. the cases of the red supergiant Betelgeuse Mackey et al 2014) and IRC−10414 ). These circumstellar structures are themselves sensitive to the presence of even a weak ISM background magnetic field of a few µG (van Marle et al 2014).…”

Section: The Case Of Runaway Cool Starsmentioning

confidence: 99%

Bow shock nebulae of hot massive stars in a magnetized medium

Meyer

Mignone

Kuiper

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

A significant fraction of OB-type, main-sequence massive stars are classified as runaway and move supersonically through the interstellar medium (ISM). Their strong stellar winds interact with their surroundings where the typical strength of the local ISM magnetic field is about 3.5-7 µG, which can result in the formation of bow shock nebulae. We investigate the effects of such magnetic fields, aligned with the motion of the flow, on the formation and emission properties of these circumstellar structures. Our axisymmetric, magneto-hydrodynamical simulations with optically-thin radiative cooling, heating and anisotropic thermal conduction show that the presence of the background ISM magnetic field affects the projected optical emission our bow shocks at Hα and [OIII] λ 5007 which become fainter by about 1-2 orders of magnitude, respectively. Radiative transfer calculations against dust opacity indicate that the magnetic field slightly diminishes their projected infrared emission and that our bow shocks emit brightly at 60 µm. This may explain why the bow shocks generated by ionizing runaway massive stars are often difficult to identify. Finally, we discuss our results in the context of the bow shock of ζ Ophiuchi and we support the interpretation of its imperfect morphology as an evidence of the presence of an ISM magnetic field not aligned with the motion of its driving star.

show abstract

Section: The Case Of Runaway Cool Starsmentioning

confidence: 99%

Bow shock nebulae of hot massive stars in a magnetized medium

Meyer

Mignone

Kuiper

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…Bladh et al 2015). The formation mechanism is also fundamentally different from the shells observed around high-mass evolved stars, where photoionization creates confined shells (Mackey et al 2014). Thermal emission from the dust in detached shells was first observed in the far-infrared by IRAS (van der Veen & Habing 1988;Waters et al 1994;Izumiura et al 1997), and more recently by AKARI and Herschel (Kerschbaum et al 2010;Izumiura et al 2011;Cox et al 2012;Mečina et al 2014).…”

Section: Introductionmentioning

confidence: 99%

A detailed view of the gas shell around R Sculptoris with ALMA

Maercker

Vlemmings

Brunner

et al. 2016

A&A

View full text Add to dashboard Cite

Context. During the asymptotic giant branch (AGB) phase, stars undergo thermal pulses − short-lived phases of explosive helium burning in a shell around the stellar core. Thermal pulses lead to the formation and mixing-up of new elements to the stellar surface. They are hence fundamental to the chemical evolution of the star and its circumstellar envelope. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star, several of which have been observed around carbon-rich AGB stars. Aims. We aim to determine the physical properties of the detached gas shell around R Sculptoris, in particular the shell mass and temperature, and to constrain the evolution of the mass-loss rate during and after a thermal pulse. Methods. We analyse 12 CO(1−0), 12 CO(2−1), and 12 CO(3−2) emission, observed with the Atacama Large Millimeter/submillimeter Array (ALMA) during Cycle 0 and complemented by single-dish observations. The spatial resolution of the ALMA data allows us to separate the detached shell emission from the extended emission inside the shell. We perform radiative transfer modelling of both components to determine the shell properties and the post-pulse mass-loss properties.Results. The ALMA data show a gas shell with a radius of 19. 5 expanding at 14.3 km s −1 . The different scales probed by the ALMA Cycle 0 array show that the shell must be entirely filled with gas, contrary to the idea of a detached shell. The comparison to single-dish spectra and radiative transfer modelling confirms this. We derive a shell mass of 4.5 × 10 −3 M with a temperature of 50 K. Typical timescales for thermal pulses imply a pulse mass-loss rate of 2.3 × 10 −5 M yr −1 . For the post-pulse mass-loss rate, we find evidence for a gradual decline of the mass-loss rate, with an average value of 1.6 × 10 −5 M yr −1 . The total amount of mass lost since the last thermal pulse is 0.03 M , a factor four higher compared to classical models, with a sharp decline in mass-loss rate immediately after the pulse. Conclusions. We find that the mass-loss rate after a thermal pulse has to decline more slowly than generally expected from models of thermal pulses. This may cause the star to lose significantly more mass during a thermal pulse cycle, which affects the lifetime on the AGB and the chemical evolution of the star, its circumstellar envelope, and the interstellar medium.

show abstract

“…WOH G64 in the Large Magellanic Cloud also shows similar nebular emission lines (Levesque et al 2009). Mackey et al (2014) proposed that Betelgeuse's wind is also externally photoionized, to explain the presence of a static neutral shell around the star (Le Bertre et al 2012). We expect on this basis that many red supergiants have photoionized winds.…”

Section: Introductionmentioning

confidence: 99%

“…We expect on this basis that many red supergiants have photoionized winds. Mackey et al (2014) showed that the winds of red supergiants could be decelerated and accumulated into a dense shell, if the wind is exposed to an external ionizing radiation field from all sides. This could have important consequences for the fate of the mass lost during the red supergiant phase, and also for any subsequent evolutionary phases and the observational characteristics of the star's eventual supernova explosion (Mackey et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Mackey et al (2014) showed that the winds of red supergiants could be decelerated and accumulated into a dense shell, if the wind is exposed to an external ionizing radiation field from all sides. This could have important consequences for the fate of the mass lost during the red supergiant phase, and also for any subsequent evolutionary phases and the observational characteristics of the star's eventual supernova explosion (Mackey et al 2014). If this mechanism is effective, then the mass lost by red supergiants could remain within the parent star cluster for much longer than if the wind is freely expanding, increasing the likelihood that secondary star formation could happen.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cold gas in hot star clusters: the wind from the red supergiant W26 in Westerlund 1

Mackey

Castro²,

Fossati

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

The massive red supergiant W26 in Westerlund 1 is one of a growing number of red supergiants shown to have winds that are ionized from the outside in. The fate of this dense wind material is important for models of second generation star formation in massive star clusters. Mackey et al. (2014, Nature, 512, 282) showed that external photoionization can stall the wind of red supergiants and accumulate mass in a dense static shell. We use spherically symmetric radiation-hydrodynamic simulations of an externally photoionized wind to predict the brightness distribution of Hα and [N II] emission arising from photoionized winds both with and without a dense shell. We analyse spectra of the Hα and [N II] emission lines in the circumstellar environment around W26 and compare them with simulations to investigate whether W26 has a wind that is confined by external photoionization. Simulations of slow winds that are decelerated into a dense shell show strongly limb-brightened line emission, with line radial velocities that are independent of the wind speed. Faster winds ( 22 km s −1 ) do not form a dense shell, have less limb-brightening, and the line radial velocity is a good tracer of the wind speed. The brightness of the [N II] and Hα lines as a function of distance from W26 agrees reasonably well with observations when only the line flux is considered. The radial velocity of the simulated winds disagrees with observations, however: the brightest observed emission is blueshifted by ≈25 km s −1 relative to the radial velocity of the star, whereas a spherically symmetric wind has the brightest emission at zero radial velocity because of limb brightening. Our results show that the bright nebula surrounding W26 must be asymmetric, and we suggest that it is confined by external ram pressure from the extreme wind of the nearby supergiant W9. We obtain a lower limit on the nitrogen abundance within the nebula of 2.35 times solar. The line ratio strongly favours photoionization over shock ionization, and so even if the observed nebula is pressure confined there should still be an ionization front and a photoionization-confined shell closer to the star that is not resolved by the current observations, which could be tested with better spectral resolution and spatial coverage.

show abstract

Interacting supernovae from photoionization-confined shells around red supergiant stars

Cited by 69 publications

References 44 publications

Bow shock nebulae of hot massive stars in a magnetized medium

Bow shock nebulae of hot massive stars in a magnetized medium

A detailed view of the gas shell around R Sculptoris with ALMA

Cold gas in hot star clusters: the wind from the red supergiant W26 in Westerlund 1

Contact Info

Product

Resources

About