A High‐Velocity Molecular Outflow from the G9.62+0.19 Star‐forming Region

2001 ◽  
Vol 549 (1) ◽  
pp. 425-432 ◽  
Author(s):  
Peter Hofner ◽  
Helmut Wiesemeyer ◽  
Thomas Henning
Keyword(s):  
High Velocity ◽  
Star Forming ◽  
Molecular Outflow

scholarly journals SMA CO (2-1) Observations of CG 30: A Protostellar Binary System with a High-Velocity Quadrupolar Molecular Outflow

2008 ◽  
Vol 686 (2) ◽  
pp. L107-L110 ◽  
Author(s):  
Xuepeng Chen ◽  
Tyler L. Bourke ◽  
Ralf Launhardt ◽  
Thomas Henning
Keyword(s):  
Binary System ◽  
High Velocity ◽  
Molecular Outflow

scholarly journals APEX CO (9-8) MAPPING OF AN EXTREMELY HIGH VELOCITY AND JET-LIKE OUTFLOW IN A HIGH-MASS STAR-FORMING REGION

2011 ◽  
Vol 743 (1) ◽  
pp. L25 ◽  
Author(s):  
Keping Qiu ◽  
Friedrich Wyrowski ◽  
Karl M. Menten ◽  
Rolf Güsten ◽  
Silvia Leurini ◽  
...  
Keyword(s):  
High Velocity ◽  
High Mass ◽  
Mass Star ◽  
Star Forming

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 Formation of Orion fingers

2020 ◽  
Vol 495 (1) ◽  
pp. 1172-1187
Author(s):  
Ross Dempsey ◽  
Nadia L Zakamska ◽  
James E Owen
Keyword(s):  
Physical Properties ◽  
Time Scales ◽  
High Velocity ◽  
Massive Stars ◽  
Hydrodynamic Instabilities ◽  
Similar Time ◽  
Dynamical Interaction ◽  
Star Forming ◽  
Common System ◽  
Bow Shocks

ABSTRACT ‘Orion fingers’ are a system of dozens of bow shocks, with the wings of shocks pointing to a common system of origin, which is centred on a dynamically disintegrating system of several massive stars. The shock heads propagate with velocities of up to 300–400 km s−1, but the formation and physical properties of the ‘bullets’ leading the shocks are not known. Here, we summarize two possible scenarios for the formation of the ‘bullets’ and the resulting bow shocks (‘fingers’). In the first scenario, bullets are self-gravitating, Jupiter-mass objects that were formed rapidly and then ejected during the strong dynamical interactions of massive stars and their discs. This scenario naturally explains the similar time-scales for the outflow of bullets and for the dynamical interaction of the massive stars, but has some difficulty explaining the observed high velocities of the bullets. In the second scenario, bullets are formed via hydrodynamic instabilities in a massive, infrared-driven wind, naturally explaining the high velocities and the morphology of outflow, but the bullets are not required to be self-gravitating. The processes that created the Orion fingers are likely not unique to this particular star-forming region and may result in free-floating, high-velocity, core-less planets.

scholarly journals Warm gas in protostellar outflows

2019 ◽  
Vol 629 ◽  
pp. A77
Author(s):  
A. I. Gómez-Ruiz ◽  
A. Gusdorf ◽  
S. Leurini ◽  
K. M. Menten ◽  
S. Takahashi ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
High Velocity ◽  
The Other ◽  
Mass Star ◽  
Intermediate Mass ◽  
Star Forming ◽  
Physical Conditions ◽  
Star Forming Regions ◽  
Low Mass ◽  
Kinematic Properties

Context. OMC-2/3 is one of the nearest embedded cluster-forming regions that includes intermediate-mass protostars at early stages of evolution. A previous CO (3–2) mapping survey towards this region revealed outflow activity related to sources at different evolutionary phases. Aims. The present work presents a study of the warm gas in the high-velocity emission from several outflows found in CO (3–2) emission by previous observations, determines their physical conditions, and makes a comparison with previous results in low-mass star-forming regions. Methods. We used the CHAMP+ heterodyne array on the APEX telescope to map the CO (6–5) and CO (7–6) emission in the OMC-2 FIR 6 and OMC-3 MMS 1-6 regions, and to observe 13CO (6–5) at selected positions. We analyzed these data together with previous CO (3–2) observations. In addition, we mapped the SiO (5–4) emission in OMC-2 FIR 6. Results. The CO (6–5) emission was detected in most of the outflow lobes in the mapped regions, while the CO (7–6) was found mostly in the OMC-3 outflows. In the OMC-3 MMS 5 outflow, a previously undetected extremely high-velocity gas was found in CO (6–5). This extremely high-velocity emission arises from the regions close to the central object MMS 5. Radiative transfer models revealed that the high-velocity gas from MMS 5 outflow consists of gas with nH2 = 104–105 cm−3 and T > 200 K, similar to what is observed in young Class 0 low-mass protostars. For the other outflows, values of nH2 > 104 cm−3 were found. Conclusions. The physical conditions and kinematic properties of the young intermediate-mass outflows presented here are similar to those found in outflows from Class 0 low-mass objects. Due to their excitation requirements, mid − J CO lines are good tracers of extremely high-velocity gas in young outflows likely related to jets.

scholarly journals Anatomy of the massive star-forming region S106

2018 ◽  
Vol 617 ◽  
pp. A45 ◽  
Author(s):  
N. Schneider ◽  
M. Röllig ◽  
R. Simon ◽  
H. Wiesemeyer ◽  
A. Gusdorf ◽  
...  
Keyword(s):  
Binary System ◽  
High Velocity ◽  
Central Area ◽  
Line Emission ◽  
Two Phase ◽  
Star Forming ◽  
Projected Length ◽  
Molecular Lines ◽  
Dark Lane ◽  
Gas Accretion

The central area (40″  × 40″) of the bipolar nebula S106 was mapped in the [O I] line at 63.2 μm (4.74 THz) with high angular (6″) and spectral (0.24 MHz) resolution, using the GREAT heterodyne receiver on board SOFIA. The spatial and spectral emission distribution of [O I] is compared to emission in the CO 16 →15, [C II] 158 μm, and CO 11 →10 lines, mm-molecular lines, and continuum. The [O I] emission is composed of several velocity components in the range from –30 to 25 km s−1. The high-velocity blue- and red-shifted emission (v = −30 to –9 km s−1 and 8 to 25 km s−1) can be explained as arising from accelerated photodissociated gas associated with a dark lane close to the massive binary system S106 IR, and from shocks caused by the stellar wind and/or a disk–envelope interaction. At velocities from –9 to –4 km s−1 and from 0.5 to 8 km s−1 line wings are observed in most of the lines that we attribute to cooling in photodissociation regions (PDRs) created by the ionizing radiation impinging on the cavity walls. The velocity range from –4 to 0.5 km s−1 is dominated by emission from the clumpy molecular cloud, and the [O I], [C II], and high-J CO lines are excited in PDRs on clump surfaces that are illuminated by the central stars. Modelling the line emission in the different velocity ranges with the KOSMA-τ code constrains a radiation field χ of a few times 104 and densities n of a few times 104 cm−3. Considering self-absorption of the [O I] line results in higher densities (up to 106 cm−3) only for the gas component seen at high blue- and red velocities. We thus confirm the scenario found in other studies that the emission of these lines can be explained by a two-phase PDR, but attribute the high-density gas to the high-velocity component only. The dark lane has a mass of ~275 M⊙ and shows a velocity difference of ~1.4 km s−1 along its projected length of ~1 pc, determined from H13CO+ 1 →0 mapping. Its nature depends on the geometry and can be interpreted as a massive accretion flow (infall rate of ~2.5 × 10−4 M⊙ yr−1), or the remains of it, linked to S106 IR/FIR. The most likely explanation is that the binary system is at a stage of its evolution where gas accretion is counteracted by the stellar winds and radiation, leading to the very complex observed spatial and kinematic emission distribution of the various tracers.

Magnetic Fields and Disks in Star-forming Regions

1993 ◽  
Vol 10 (3) ◽  
pp. 247-249 ◽  
Author(s):  
C.M. Wright ◽  
D.K. Aitken ◽  
C.H. Smith ◽  
P.F. Roche
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Transverse Component ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
Star Forming ◽  
Star Forming Regions ◽  
Molecular Outflow ◽  
The Magnetic Field

AbstractThe star-formation process is an outstanding and largely unsolved problem in astrophysics. The role of magnetic fields is unclear but is widely considered to be important at all stages of protostellar evolution, from cloud collapse to ZAMS. For example, in some hydromagnetic models, the field may assist in removing angular momentum, thereby driving accretion and perhaps bipolar outflows.Spectropolarimetry between 8 and 13μm provides information on the direction of the transverse component of a magnetic field through the alignment of dust grains. We present results of 8–13μm spectropolarimetric observations of a number of bipolar molecular outflow sources, and compare the field directions observed with the axes of the outflows and putative disk-like structures observed to be associated with some of the objects. There is a strong correlation, though so far with limited statistics, between the magnetic field and disk orientations. We compare our results with magnetic field configurations predicted by current models for hydromagnetically driven winds from the disks around Young Stellar Objects (YSOs). Our results appear to argue against the Pudritz and Norman model and instead seem to support the Uchida and Shibata model.

scholarly journals A VLBI Study of H2O Maser Spots Associated with a Molecular Outflow ρ Oph-East

1994 ◽  
Vol 140 ◽  
pp. 60-61
Author(s):  
Takahiro Iwata ◽  
Hiroshi Takaba ◽  
Kin-Ya Matsumoto ◽  
Seiji Kameno ◽  
Noriyuki Kawaguchi
Keyword(s):  
Molecular Cloud ◽  
Observational Evidence ◽  
Molecular Gas ◽  
Mass Star ◽  
Dynamical Interaction ◽  
Star Forming ◽  
Star Forming Regions ◽  
Molecular Outflow ◽  
Low Mass ◽  
A Site

A molecular outflow is one of the most conspicuous active phenomena associated with protostars, and the kinetic energy of its outflowing mass is as large as that of random motions of ambient molecular cloud, which suggests that outflow has dynamically influence on ambient molecular gas. Possible observational evidence which suggests the existence of dynamical interaction between molecular outflow and ambient molecular cloud has been detected in several star forming regions (Fukui et al. 1986; Iwata et al. 1988). Recent detections of H2O maser emission associated with low-mass protostars (e.g. Comoretto et al. 1990) also suggest that there still exist active phenomena in the low-mass star forming regions.Molecular outflow ρ Oph-East, discovered toward a low-mass protostar IRAS 16293-2422 (Fukui et al. 1986), has been known as a site of dynamical interaction between molecular outflowing gas and ambient molecular cloud by CO and NH3 observation (Mizuno et al. 1990). Existence of several strong H2O maser spots (Wilking & Claussen 1987; Wotten 1989; Terebey et al. 1992) also suggests that active phenomena are occurring in this region. In this paper, we report our result of H2O maser observation for molecular outflow ρ Oph-East with milli-arcsecond resolution by VLBI.

A Swept-Up Molecular Bubble in L1551

1989 ◽  
Vol 120 ◽  
pp. 260-263
Author(s):  
Saeko S. Hayashi ◽  
Masahiko Hayashi ◽  
Norio Kaifu
Keyword(s):  
Uv Radiation ◽  
Spectral Type ◽  
Stellar Wind ◽  
Shell Structures ◽  
The Sun ◽  
Dark Cloud ◽  
Star Forming ◽  
Star Forming Regions ◽  
Molecular Outflow ◽  
Dominant Activity

The environment of the young stellar object IRS5 in L1551 dark cloud is a representative of the “protostellar disk and outflow” systems found in star forming regions. The bipolar molecular outflow there was discovered as the first of its kind a decade ago (Snell, Loren, and Plambeck 1980). Its location in the sky, that is, its proximity (160 pc), isolation, and its almost edge-on inclination have favored the observation in great detail. IRS5 is thought to have the spectral type G - K (Mundt et al. 1985) similar to the Sun, with its dominant activity in the stellar wind, and not in the UV radiation as in massive protostars. The blueshifted and redshifted outflow lobes are clearly resolved into a pair of shell structures. The successive studies, mostly in CO lines, have led to a model of the outflow in which the molecular material is accelerated at the edge of a cavity evacuated by the protostellar wind (e.g. Uchida et al. 1987, Rainey et al. 1987, Moriarty-Schieven and Snell 1988).

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