Spatially extended K I λ7699 emission in the nebula of VY CMa

Kinematics and geometry

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Long-slit echelle spectra reveal bright extended emission from the K I λ7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of the circumstellar environment of VY CMa. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight through the nebula intersect multiple distinct velocity components. A faint 'halo' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km s-1 with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the stellar surface.

Original languageEnglish (US)
JournalMonthly Notices of the Royal Astronomical Society
Volume349
Issue number2
DOIs
StatePublished - Apr 1 2004
Externally publishedYes

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nebulae
kinematics
geometry
stars
slits
reflection nebulae
velocity structure
resonance lines
volcanic eruptions
line of sight
halos
volcanic eruption
scattering
probe
shell
probes
atoms

Keywords

  • Circumstellar matter
  • Stars: evolution
  • Stars: individual: VY CMa
  • Stars: mass-loss

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

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title = "Spatially extended K I λ7699 emission in the nebula of VY CMa: Kinematics and geometry",
abstract = "Long-slit echelle spectra reveal bright extended emission from the K I λ7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of the circumstellar environment of VY CMa. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight through the nebula intersect multiple distinct velocity components. A faint 'halo' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km s-1 with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the stellar surface.",
keywords = "Circumstellar matter, Stars: evolution, Stars: individual: VY CMa, Stars: mass-loss",
author = "Nathan Smith",
year = "2004",
month = "4",
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doi = "10.1111/j.1365-2966.2004.07718.x",
language = "English (US)",
volume = "349",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
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T1 - Spatially extended K I λ7699 emission in the nebula of VY CMa

T2 - Kinematics and geometry

AU - Smith, Nathan

PY - 2004/4/1

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N2 - Long-slit echelle spectra reveal bright extended emission from the K I λ7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of the circumstellar environment of VY CMa. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight through the nebula intersect multiple distinct velocity components. A faint 'halo' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km s-1 with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the stellar surface.

AB - Long-slit echelle spectra reveal bright extended emission from the K I λ7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of the circumstellar environment of VY CMa. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight through the nebula intersect multiple distinct velocity components. A faint 'halo' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km s-1 with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the stellar surface.

KW - Circumstellar matter

KW - Stars: evolution

KW - Stars: individual: VY CMa

KW - Stars: mass-loss

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