High-velocity molecular gas in the dark cloud L1529

1982 ◽  
Vol 255 ◽  
pp. L119 ◽  
Author(s):  
S. M. Lichten
Keyword(s):  
High Velocity ◽  
Molecular Gas ◽  
Dark Cloud

Structure and kinematics of molecular jets

1986 ◽  
Vol 64 (4) ◽  
pp. 431-433 ◽  
Author(s):  
Ronald L. Snell
Keyword(s):  
Stellar Wind ◽  
High Velocity ◽  
Observational Studies ◽  
Molecular Gas ◽  
Dark Cloud ◽  
Star Forming ◽  
Molecular Outflows ◽  
Star Forming Regions ◽  
Cloud Material

Observational studies of the structure and kinematics of the supersonic molecular gas in star-forming regions are reviewed. These studies have suggested that the bulk of the high-velocity gas may be ambient-cloud material swept up by a collimated stellar wind. The actual structures of these outflows, however, are poorly understood. One source that may provide a better understanding of molecular outflows is that in the nearby dark cloud L1551. New observations of this outflow are presented and discussed in context of the models proposed by Snell and Schloerb.

Morphology and Energetics of the Molecular Gas within a Core and a Diffuse Region in the Filamentary Dark Cloud GF 9

2000 ◽  
Vol 120 (1) ◽  
pp. 393-406 ◽  
Author(s):  
David R. Ciardi ◽  
Charles E. Woodward ◽  
Dan P. Clemens ◽  
David E. Harker ◽  
Richard J. Rudy
Keyword(s):  
Molecular Gas ◽  
Dark Cloud ◽  
Diffuse Region

scholarly journals Shocked Molecular Hydrogen from Star Forming Regions

1987 ◽  
Vol 115 ◽  
pp. 181-181 ◽  
Author(s):  
Adair P. Lane ◽  
John Bally
Keyword(s):  
Shock Waves ◽  
High Velocity ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Young Stars ◽  
Emission Lines ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Post Shock

Near infrared (2 micron) emission lines from molecular hydrogen provide a powerful probe of the morphology and energetics of outflows associated with stellar birth. The H2 emission regions trace the location of shock waves formed when the high velocity outflow from young stars encounters dense quiescent gas. Since H2 is the dominant coolant of the hot post-shock molecular gas, the H2 lines provide a measure of the fraction of the total mechanical luminosity radiated away from the cloud.

scholarly journals The Molecular Outflow and CO Bullets in HH111

1997 ◽  
Vol 182 ◽  
pp. 141-152 ◽  
Author(s):  
J. Cernicharo ◽  
R. Neri ◽  
Bo Reipurth
Keyword(s):  
High Velocity ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Kinetic Temperature ◽  
Low Velocity ◽  
Molecular Outflow ◽  
Hh Objects ◽  
Physical Phenomena ◽  
First Time

We present high angular resolution observations of the molecular outflow associated with the optical jet and HH objects of the HH111 system. Interferometric observations in the CO J =2–1 and J =1–0 lines of the high velocity bullets associated with HH111 are presented for the first time. The molecular gas in these high velocity clumps has a moderate kinetic temperature and a mass of a few 10–4 M⊙ per bullet. We favor the view that HH jets and CO bullets, which represent different manifestations of the same physical phenomena, are driving the low-velocity molecular outflow.

scholarly journals Study of the 13CO/C18O abundance ratio towards the filamentary infrared dark cloud IRDC 34.43 + 0.24

2019 ◽  
Vol 36 ◽  
Author(s):  
M. B. Areal ◽  
S. Paron ◽  
M. E. Ortega ◽  
L. Duvidovich
Keyword(s):  
Molecular Clouds ◽  
Galactic Plane ◽  
Abundance Ratio ◽  
Young Stellar Objects ◽  
Molecular Gas ◽  
Accurate Analysis ◽  
Good Tool ◽  
Dark Cloud ◽  
Average Value ◽  
Far Ultraviolet

Abstract Nowadays, there are several observational studies about the 13CO/C18O abundance ratio ( $X^{13/18}$ ) towards nearby molecular clouds. These works give observational support to the C18O selective photodissociation due to the interaction between the far ultraviolet (FUV) radiation and the molecular gas. It is necessary to increase the sample of molecular clouds located at different distances and affected in different ways by nearby or embedded H ii regions and OB associations to study the selective photodissociation. Using 12CO, 13CO, and C18O J = 1–0 data obtained from the FOREST unbiased Galactic plane imaging survey performed with the Nobeyama 45-m telescope, we analyse the filamentary infrared dark cloud IRDC $34.43+0.24$ located at the distance of about 3.9 kpc. This infrared dark cloud (IRDC) is related to several H ii regions and young stellar objects. Assuming local thermodynamic equilibrium, we obtain: $0.8 \times 10^{16} <$ N(13CO) $<4 \times 10^{17}$ cm–2 (average value $= 4.2 \times 10^{16}$ cm–2), $0.6 \times 10^{15} <$ N(C18O) $<4.4 \times 10^{16}$ cm–2 (average value $= 5.0 \times 10^{15}$ cm–2), and 3 $<$ $X^{13/18}$ $<$ 30 (average $= 8$ ) across the whole IRDC. Larger values of $X^{13/18}$ were found towards portions of the cloud related to the H ii regions associated with the N61 and N62 bubbles and with the photodissociation regions, precisely the regions in which FUV photons are strongly interacting with the molecular gas. Our result represents an observational support to the C18O selectively photodissociation phenomenon occurring in a quite distant filamentary IRDC. Additionally, based on IR data from the Hi-GAL survey, the FUV radiation field was estimated in Habing units, and the dust temperature (T $_{dust}$ ) and H2 column density (N(H2)) distribution were studied. Using the average of N(H2), values in close agreement with the ‘canonical’ abundance ratios [H2]/[13CO] and [H2]/[C18O] were derived. However, the obtained ranges in the abundance ratios show that if an accurate analysis of the molecular gas is required, the use of the ‘canonical’ values may introduce some bias. Thus, it is important to consider how the gas is irradiated by the FUV photons across the molecular cloud. The analysis of $X^{13/18}$ is a good tool to perform that. Effects of beam dilution and clumpiness were studied.

scholarly journals Bipolar Outflows and Stellar Jets

1987 ◽  
Vol 115 ◽  
pp. 213-237 ◽  
Author(s):  
Ronald L. Snell
Keyword(s):  
Physical Properties ◽  
High Velocity ◽  
Molecular Clouds ◽  
Early Stage ◽  
Young Stellar Objects ◽  
Molecular Gas ◽  
Bipolar Outflows ◽  
Stellar Objects ◽  
Stellar Jets ◽  
Almost All

A wealth of data is now available on the energetic mass outflows that are associated with young stellar objects. This phenomenon is thought to occur at a very early stage in the evolution of stars of almost all masses. The discovery of this energetic event was first made through observations of the rapidly expanding molecular gas that surrounds many of these young stellar objects. A review of the physical properties, including the energetics and morphology, of the expanding molecular gas is presented in this paper. In addition, the role these energetic winds play in affecting the dynamics of the parental molecular clouds is also discussed. Finally, the results of detailed studies of the structure and kinematics of the high velocity molecular gas are reviewed and the evidence for existance of wind-swept cavities and molecular shells within the clouds are presented.

Dust extinction and molecular gas in the dark cloud IC 5146

1994 ◽  
Vol 429 ◽  
pp. 694 ◽  
Author(s):  
Charles J. Lada ◽  
Elizabeth A. Lada ◽  
Dan P. Clemens ◽  
John Bally
Keyword(s):  
Molecular Gas ◽  
Dark Cloud ◽  
Dust Extinction
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