The circumstellar and nebular environment of the Becklin-Neugebauer object - 2-5 micron wavelength spectroscopy

Scoville, N. Z.; Kleinmann, S. G.; Hall, Donald N. B.; Ridgway, S. T.

doi:10.1086/161526

Cited by 153 publications

(172 citation statements)

References 0 publications

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“…How do these general features compare with the data published by Scoville et al (1983) which were observed during several observing runs between December 1977 and February 1981, hence about 30 years prior to our observations. The general CO line structure with two strong absorption features plus one red-shifted emission peak are largely the same.…”

Section: Resultssupporting

confidence: 78%

“…Also the overall extent of the emission is quite similar. Compared to our measured values of ∼−15, ∼+9 and ∼20 km s −1 for the three components, Scoville et al (1983) report for the corresponding features velocities of −18, +9 and +20 km s −1 . While two velocities agree well, the most blue-shifted absorption peak appears to have shifted a little bit between the two observations.…”

Section: Resultscontrasting

confidence: 69%

“…However, given that their spectral resolution was more than a factor 2 lower than that of the new CRIRES data (7 versus 3 km s −1 ), we refrain from further interpretation of this. Furthermore, Scoville et al (1983) identify two more absorption features, one at −3 km s −1 and one at +30 km s −1 . Regarding the −3 km s −1 component we are not able to infer any changes because that features lies very close to the telluric emission which obscures any reliable signature there.…”

Section: Resultsmentioning

confidence: 88%

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Disk and outflow signatures in Orion-KL: the power of high-resolution thermal infrared spectroscopy

Beuther¹,

Linz²,

Bik³

et al. 2010

A&A

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Context. The Orion-KL region contains the closest examples of high-mass accretion disk candidates. Studying their properties is an essential step in studying high-mass star formation. Aims. Resolving the molecular line emission at high spatial and spectral resolution in the immediate environment of the exciting sources to infer the physical properties of the associated gas. Methods. We used the CRIRES high-resolution spectrograph mounted on the VLT to study the ro-vibrational 12 CO, 13 CO, the Pfund β, and H 2 emission between 4.59 and 4.72 μm wavelengths toward the BN object, the disk candidate source n, and a proposed dust density enhancement IRC3. Results. We detected CO absorption and emission features toward all three targets. Toward the BN object, the data partly confirm the results obtained more than 25 years ago; however, we also identify several new features. While the blue-shifted absorption is likely caused by outflowing gas, toward the BN object we detect CO in emission extending in diameter to ∼3300 AU with a velocity structure close to the v lsr . Although at the observational spectral resolution limit, the 13 CO line width of that feature increases with energy levels, consistent with a disk origin. If one also attributes the extended CO emission to a disk origin, its extent is consistent with other massive disk candidates in the literature. For source n, we also find the blueshifted CO absorption likely from an outflow. However, it also exhibits a narrower range of redshifted CO absorption and adjacent weak CO emission, consistent with infalling motions. We do not spatially resolve the emission for source n. For both sources we conduct a Boltzmann analysis of the 13 CO absorption features and find temperatures between 100 and 160 K, and H 2 column densities of a few times 10 23 cm −2 . The observational signatures from IRC3 are very different with only weak absorption against a much weaker continuum source. However, the CO emission is extended and shows wedge-like position velocity signatures consistent with jet-entrainment of molecular gas, potentially associated with the Orion-KL outflow system. We also present and discuss the Pfund β and H 2 emission in the region. Conclusions. This analysis toward the closest high-mass disk candidates outlines the power of high spectral and spatial resolution mid-infrared spectroscopy for studying the gas properties close to young massive stars. We will extend qualitatively similar studies to larger samples of high-mass young stellar objects to constrain the physical properties of the dense innermost gas structures in more detail and in a statistical sense.

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Section: Resultssupporting

confidence: 78%

Section: Resultscontrasting

confidence: 69%

Section: Resultsmentioning

confidence: 88%

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Disk and outflow signatures in Orion-KL: the power of high-resolution thermal infrared spectroscopy

Beuther¹,

Linz²,

Bik³

et al. 2010

A&A

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“…5.1), the 20.5 km s −1 component could be related to shocks as well, maybe associated with the explosive dynamical interaction that took place in Orion KL (Gómez et al 2005;Zapata et al 2011a) and more especifically to shocks associated with the BN object. This is consistent with the fact that the BN object in Orion presents significantly high CO and 13 CO emission at ∼20 km s −1 (Scoville et al 1983). Observations combining both single-dish and interferometric data are required to definitely identify the spatial region in Orion KL emitting the bulk of emission at 20 km s −1 .…”

Section: So and So 2 As Tracers Of Shocks And Hot Gassupporting

confidence: 75%

A line confusion-limited millimeter survey of Orion KL

Esplugues

Tercero

Cernicharo

et al. 2013

A&A

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Context. We present a study of the sulfur-bearing species detected in a line confusion-limited survey towards Orion KL performed with the IRAM 30-m telescope in the frequency range 80−281 GHz. Aims. This study is part of an analysis of the line survey divided into families of molecules. Our aim is to derive accurate physical conditions, as well as molecular abundances, in the different components of Orion KL from observed SO and SO 2 lines. Methods. As a starting point, we assumed local thermodynamic equilibrium (LTE) conditions obtain rotational temperatures. We then used a radiative transfer model, assuming either LVG or LTE excitation to derive column densities of these molecules in the different components of Orion KL. = 1 and for several undetected sulfur-bearing species. In addition, we present 2 × 2 maps around Orion IRc2 of SO 2 transitions with energies from 19 to 131 K and also maps with four transitions of SO, 34 SO, and 34 SO 2 . We observe an elongation of the gas along the NE-SW direction. An unexpected emission peak appears at 20.5 km s −1 in most lines of SO and SO 2 . A study of the spatial distribution of this emission feature shows that it is a new component of a few arcseconds (∼5 ) in diameter, which lies ∼4 west of IRc2. We suggest the emission from this feature is related to shocks associated to the BN object. Conclusions. The highest column densities for SO and SO 2 are found in the high-velocity plateau (a region dominated by shocks) and in the hot core. These values are up to three orders of magnitude higher than the results for the ridge components. We also find high column densities for their isotopologues in both components. Therefore, we conclude that SO and SO 2 are good tracers, not only of regions affected by shocks, but also of regions with warm dense gas (hot cores).

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“…The density in this region would then be enhanced due to a swept-up wind, and was proposed to be a few hundred au away from the central stars. Scoville et al (1983) observed the Becklin-Neugebauer object (2MASS05351411-0522227) in OMC-1, a young, hot star which also has Na i 2.2 μm emission. They locate the Na i region outside the H ii region and propose that the Balmer bound-free continuum emission is more likely to excite the atoms.…”

Section: The Origin Of the Na I Emissionmentioning

confidence: 99%

Neutral and ionised gas around the post-red supergiant IRC +10 420 at AU size scales

Oudmaijer

Wit

2013

A&A

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Context. IRC +10 420 is one of the few known massive stars in rapid transition from the red supergiant phase to the Wolf-Rayet or luminous blue variable phase. Aims. The star has an ionised wind and using the Brγ line we assess the mass-loss on spatial scales of ∼1 AU. Methods. We present new VLT Interferometer AMBER data which are combined with all other AMBER data present in the literature. The final dataset covers a position angle range of ∼180 • and baselines up to 110 m. The spectrally dispersed visibilities, differential phases and line flux are conjointly analysed and modelled. We also present the first AMBER/FINITO observations which cover a larger wavelength range and allow us to observe the Na i doublet at 2.2 μm. The data are complemented by X-Shooter data, which provide a higher spectral resolution view.Results. The Brγ emission line and the Na i doublet are both spatially resolved. After correcting the AMBER data for the fact that the lines are not spectrally resolved, we find that Brγ traces a ring with a diameter of 4.18 mas, in agreement with higher spectral resolution data. We consider a geometric model in which the Brγ emission emerges from the top and bottom rings of an hour-glass shaped structure, viewed almost pole-on. It provides satisfactory fits to most visibilities and differential phases. The fact that we detect line emission from a neutral metal like Na i within the ionised region, a very unusual occurrence, suggests the presence of a dense pseudo-photosphere. Conclusions. The ionised wind can be reproduced with a polar wind, which could well have the shape of an hour-glass. Closer in, the resolved Na i emission is found to occur on scales barely larger than the continuum. This fact and that many yellow hypergiants exhibit this comparatively rare emission hints at the presence of a "Yellow" or even "White Wall" in the Hertzsprung-Russell diagram, preventing them from visibly evolving to the blue.

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The circumstellar and nebular environment of the Becklin-Neugebauer object - 2-5 micron wavelength spectroscopy

Cited by 153 publications

References 0 publications

Disk and outflow signatures in Orion-KL: the power of high-resolution thermal infrared spectroscopy

Disk and outflow signatures in Orion-KL: the power of high-resolution thermal infrared spectroscopy

A line confusion-limited millimeter survey of Orion KL

Neutral and ionised gas around the post-red supergiant IRC +10 420 at AU size scales

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