Destruction of the Environment of the BN‐KL Nebula

Salas, Luis; Rosado, M.; Cruz-González, I.; Gutiérrez, L.; Váldez, Jorge; Bernal, A.; Luna, Esther Martínez; Baraza, Elena; Lazo, Francisco

doi:10.1086/306695

Cited by 33 publications

(49 citation statements)

References 33 publications

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“…For J-type shocks, the maximum brightness which we obtain is for a shock of 20 km s −1 impacting on material of pre-shock density 5 10 6 cm −3 , a model reminiscent of that of Salas et al (1999) but with a higher preshock density. Our shock model yields a post-shock density of 7.6 10 8 cm −3 at 50 K and 3.8 10 9 cm −3 at 10 K. The v = 1−0 S(1) line brightness, integrated along the direction of propagation of the shock, is 1.6 10 −6 Wm −2 sr −1 .…”

Section: The Rôle Of Shocksmentioning

confidence: 64%

“…Models have tended to explore fast shocks, for example of 200 km s −1 , in order to explain the very broad profiles of H 2 emission lines, which have a total extent of up to 150 km s −1 . Earlier attempts to model lineshapes, emission line brightness (specific intensity) ratios and absolute brightness in terms of a global outflow, reviewed in some detail in Salas et al (1999), have not proved successful. Salas et al (1999) however suggest that the following scenario matches their spectrally (24 km s −1 ) and spatially (2 ) resolved data for the H 2 v = 1−0 S(1) line in this region.…”

Section: Introductionmentioning

confidence: 99%

“…Earlier attempts to model lineshapes, emission line brightness (specific intensity) ratios and absolute brightness in terms of a global outflow, reviewed in some detail in Salas et al (1999), have not proved successful. Salas et al (1999) however suggest that the following scenario matches their spectrally (24 km s −1 ) and spatially (2 ) resolved data for the H 2 v = 1−0 S(1) line in this region. A 230 km s −1 spherical wind emanates from IRc2/BN impinging on a clumpy molecular cloud, where clumps have a preshock density of between 5 and 6 10 5 cm −3 .…”

Section: Introductionmentioning

confidence: 99%

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H₂infrared emission and the formation of dense structures in the Orion molecular cloud

Vannier

Lemaire

Field

et al. 2001

A&A

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Abstract.Observations are reported of IR emission of H2 from a region of the Orion molecular cloud (OMC1) between the Becklin-Neugebauer object and IRc2 to the north and the Trapezium stars to the south. Data were obtained using the ESO 3.6 m telescope in the K-band around 2 µm with the ADONIS adaptive optics system. Images of H2 v = 1−0 S(1) show a spatial resolution of ∼0.15 . Detailed investigations of the distribution of sizes of structures in our images have been performed by area-perimeter analysis, Fourier analysis and brightness distribution studies. These demonstrate that structure is not fractal but shows a preferred scales of between 3 10 −3 and 4 10 −3 pc. In an attempt to estimate the density in observed structures, predictions of both shock models and photodissociation region models have been compared with measured emission brightness in the H2 v = 1−0 S(1) line. Magnetic (C-type) shocks with velocities of 30 km s −1 and pre-shock densities of 10 6 cm −3 yield the best representation of our data, notwithstanding significant discrepancies for the brightness ratio between v = 2−1 S(1) and v = 1−0 S(1) lines. Our results show that post-shock densities are several times 10 7 cm −3 . This is sufficiently high that the passage of C-type shocks in Orion yields gravitational instability which may in turn trigger star formation in the post-shock gas.

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Section: The Rôle Of Shocksmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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H₂infrared emission and the formation of dense structures in the Orion molecular cloud

Vannier

Lemaire

Field

et al. 2001

A&A

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“…2, would yield data which provide a useful test of the model proposed. Existing data in Chrysostomou et al (1997) or Salas et al (1999) is of sufficient spectral resolution but has a spatial resolution of no better than ∼1. 6.…”

Section: The Influence Of θ 1 C Orimentioning

confidence: 99%

H₂excitation imaging of the Orion Molecular Cloud

Kristensen

Gustafsson

Field

et al. 2003

A&A

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Abstract.Observations are reported of IR emission in H 2 , around 2 µm in the K-band, obtained with the ESO 3.6 m telescope using the ADONIS adaptive optics system. Data cover a region of the Orion Molecular Cloud north of the Trapezium stars and SW of the Becklin-Neugebauer object. Excellent seeing yielded diffraction limited images in the v = 2−1 S(1) line at 2.247 µm. Excitation temperature images were created by combining these data with similar data for H 2 emission in the v = 1−0 S(1) line reported earlier ). Shock models are used to estimate densities in emitting clumps of material. In local zones with high excitation temperatures, post-shock densities are found to be as high as several times 10 8 cm −3 , an order of magnitude denser than our previous estimates. We propose that the nature of these zones is dictated by the combined activity of shocks, which create dense structures, and the powerful radiation field of θ 1 C Ori which photoevaporates the boundaries of these structures.

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“…It has a FWZP of about 35 km s −1 (the "18 km s −1 flow") and a spatial extension of >20 × 10 (Masson et al 1987). The shocks that inevitably are created when the high velocity flow plunges into the surrounding medium have been studied in emission from highly rotationally excited CO and vibrationally excited H 2 (Watson et al 1985;Salas et al 1999;Gustafsson et al 2003;Kristensen et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

Wirström

Bergman

Olofsson

et al. 2006

A&A

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Aims. The very high main beam efficiency (90%) of the telescope on the sub-millimetre wave satellite Odin, in combination with the small calibration errors in the absence of atmospheric attenuation, assures that observed line brightness temperatures are very accurately determined. Based on this, we attempt to determine the column density distribution of H 2 , and the ortho-water abundance, in the Orion KL region. Methods. We have, for the first time, mapped the 12 CO J = 5−4 emission in a 7 × 7 region covering Orion KL, observed simultaneously with a 13 CO J = 5−4 map. Also presented are C 18 O J = 5−4 emission data at four different positions and a C 17 O J = 5−4 emission spectrum detected towards the Orion KL position. The Odin mapping was performed at 1 spacing (beam full width at half maximum 126 at 557 GHz). Results. The CO J = 5−4 narrow line emission from this region mainly arises in the warm, dense gas at the interface (the photondominated region) between the M 42 H ii region and the Orion A molecular cloud, the Orion PDR. The 12 CO and 13 CO J = 5−4 emission maps have been used to determine the column density distribution of H 2 gas across the Orion KL region. The results have been verified by comparing to column densities obtained using the decidedly optically thin C 18 O emission as input to the RADEX radiative transfer code. We find H 2 column densities ranging from 5 × 10 21 cm −2 at map edges to 7× 10 22 cm −2 at the molecular ridge. The mass of the gas in the mapped region is estimated to be 480 M , of which 320 M is situated towards the molecular ridge. We estimate that about half of this mass belongs to the warm Orion PDR interface layer. Finally, based on data from the positions where C 18 O J = 5−4 has been observed, we estimate the ortho-water abundance in the Orion PDR layer to be ≥8 × 10 −8 , higher than previously estimated.

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Destruction of the Environment of the BN‐KL Nebula

Cited by 33 publications

References 33 publications

H₂infrared emission and the formation of dense structures in the Orion molecular cloud

H₂infrared emission and the formation of dense structures in the Orion molecular cloud

H₂excitation imaging of the Orion Molecular Cloud

Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

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Destruction of the Environment of the BN‐KL Nebula

Cited by 33 publications

References 33 publications

H2infrared emission and the formation of dense structures in the Orion molecular cloud

H2infrared emission and the formation of dense structures in the Orion molecular cloud

H2excitation imaging of the Orion Molecular Cloud

Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

Contact Info

Product

Resources

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H₂infrared emission and the formation of dense structures in the Orion molecular cloud

H₂infrared emission and the formation of dense structures in the Orion molecular cloud

H₂excitation imaging of the Orion Molecular Cloud