Observations of the early stages in the formation of an LBV shell

González, R. F.; Koenigsberger, Gloria

doi:10.1051/0004-6361/201322980

Cited by 4 publications

(1 citation statement)

References 20 publications

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“…As additional effect to that of the progenitor's stellar motion, this naturally leads to asymmetric and inhomogeneous cavities in which the supernova blastwave will expand. This particularly affects high-mass stars evolving through eruptive stellar evolutionary stages such as so-called luminous blue variable or Wolf-Rayet phases (González & Koenigsberger 2014;Humphreys et al 2017), characterised by the sudden inflation of the star together with an increase of the star's mass-loss rate and wind velocity. This results in the ejection of dense shells of envelope material into the stellar surroundings (Sanyal et al 2017;Gräfener et al 2017;Grassitelli et al 2018).…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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Spitzerinfrared spectrograph point source classification in the Small Magellanic Cloud

Ruffle

Kemper

Jones

et al. 2015

Mon. Not. R. Astron. Soc.

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The Magellanic clouds are uniquely placed to study the stellar contribution to dust emission. Individual stars can be resolved in these systems even in the mid-infrared, and they are close enough to allow detection of infrared excess caused by dust. We have searched the Spitzer Space Telescope data archive for all Infrared Spectrograph (IRS) staring-mode observations of the Small Magellanic Cloud (SMC) and found that 209 Infrared Array Camera (IRAC) point sources within the footprint of the Surveying the Agents of Galaxy Evolution in the Small Magellanic Cloud (SAGE-SMC) Spitzer Legacy programme were targeted, within a total of 311 staring mode observations. We classify these point sources using a decision tree method of object classification, based on infrared spectral features, continuum and spectral energy distribution shape, bolometric luminosity, cluster membership and variability information. We find 58 asymptotic giant branch (AGB) stars, 51 young stellar objects (YSOs), 4 post-AGB objects, 22 Red Supergiants (RSGs), 27 stars (of which 23 are dusty OB stars), 24 planetary nebulae (PNe), 10 Wolf-Rayet (WR) stars, 3 H ii regions, 3 R Coronae Borealis (R CrB) stars, 1 Blue Supergiant and 6 other objects, including 2 foreground AGB stars. We use these classifications to evaluate the success of photometric classification methods reported in the literature.

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The enigmatic binary system HD 5980

Hillier

Koenigsberger

Nazé

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The Small Magellanic Cloud multiple system HD 5980 contains a luminous blue variable (LBV) that underwent a major eruption in 1994, and whose current spectrum is that of a hydrogen-rich Wolf–Rayet (WR) star. Since the eruption, the wind mass-loss rate has been declining while wind speeds have been steadily increasing. Observations obtained in 2014 when Star A (the LBV) eclipses Star B indicate that the fitted mass-loss rate and luminosity have reached the lowest values ever determined for such spectra: $\dot{M}$ = 4.5 × 10−5$\mathrm{M}_\odot \, \hbox{yr}^{-1}$, L = 1.7 × 106 L⊙. In addition, the radius of the LBV’s continuum-emitting region is similar to that derived from the eclipse light curves of the late 1970s. Hence, it appears to have attained a similar ‘low’ state to that of the late 1970s. While a good fit to the emission spectrum is obtained using a cmfgen model, there are discrepancies in the UV. In particular, the extent of the observed absorption profiles is ∼1000 km s−1 greater than predicted by the emission-line intensities. Further, HST UV observations obtained in 2016, when Star A is eclipsed by Star B, show unusual P Cygni profiles that are not easily explained. Surprisingly the 2016 emission-line spectrum is similar to that at the opposite eclipse obtained in 2014. The complex UV profiles are likely to arise as a consequence of the dynamics of the wind–wind collision and radiative braking, both of which will cause significant departures from spherical symmetry, and have a strong orbital phase dependence. However, other scenarios, such as intrinsically aspherical winds, cannot be ruled out.

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Observations of the early stages in the formation of an LBV shell

Cited by 4 publications

References 20 publications

Wind nebulae and supernova remnants of very massive stars

Wind nebulae and supernova remnants of very massive stars

Spitzerinfrared spectrograph point source classification in the Small Magellanic Cloud

The enigmatic binary system HD 5980

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