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 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 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.

Discovery of an Extremely High Velocity, Massive, and Compact Molecular Outflow in Norma

2008 ◽  
Vol 672 (1) ◽  
pp. 391-397 ◽  
Author(s):  
Leonardo Bronfman ◽  
Guido Garay ◽  
Manuel Merello ◽  
Diego Mardones ◽  
Jorge May ◽  
...  
Keyword(s):  
High Velocity ◽  
Molecular Outflow

scholarly journals Large scale interaction of the outflow and quiescent gas in Orion

1991 ◽  
Vol 147 ◽  
pp. 456-457
Author(s):  
J. Martin-Pintado ◽  
A. Rodriguez-Franco ◽  
R. Bachiller
Keyword(s):  
Spatial Distribution ◽  
High Velocity ◽  
Large Scale ◽  
High Sensitivity ◽  
Molecular Flow ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Transition Analysis ◽  
Molecular Outflow ◽  
Hh Objects

The IRAM 30-m radiotelescope have been used to obtain, with high angular resolution, the spatial distribution and the physical conditions of the quiescent gas in Orion A, and to search for high velocity molecular gas far away from the well known molecular outflow around IRc2. To study the quiescent gas we mapped a region of 200″×300″ around IRc2 in the J=12-11 and J=16-15 lines of HC3N with angular resolutions of 22″ and 17″ respectively. The left panel of Fig. 1 shows the spatial distribution of the high density quiescent gas around IRc2 for different radial velocities. Beside the already known molecular ridge north of IRc2 (see e. g. Bartla et al. 1983), we find four very thin (nearly unresolved) and long filaments, like “fingers”, stretching from IRc2 to the north and west. The deconvolved size of the longest fingers is ≈180″×15″. From a multi-transition analysis of the HC3N emission we derive H2 densities of 1−8 105 cm−3, kinetic temperatures larger than 40 K and masses of ≈10 Mo. Our high sensitivity observations of the J=2-1 line of CO at selected positions (see right panel ib Fig. 1) show widespread molecular gas with high velocities wings over the region where the molecular fingers and the HH objects are observed (see Fig.1). The high velocity emission occurs over a range of ±40 kms−1. This high velocity gas is more extended (up to 150″ from IRc2) than the very compact (40″) and well studied molecular outflow around IRc2 (see e.g. Wilson et al. 1986). The terminal velocities of the CO wings decrease from 100 km s−1 (corresponding to the very fast molecular flow) to the typical terminal velocities of the extended high velocity gas when the distance to IRc2 changes from 40″ to 60″. The origin of the large scale high velocity gas is unknown, but it is very likely the link between the very compact (40″) and fast (±100 km s−1) molecular outflow around IRc2 and the ionized high velocity gas and the HH objects (Martín-Pintado et al. 1990). The mass, momentum and energy of the extended high velocity gas are crudely estimated to be ≈1 Mo, ≈20 Mo km s−1 and ≈2 1045 erg respectively (i.e. a factor of ≈10 smaller than those of the fast molecular outflow). The location, at the edges of the molecular fingers, and the proper motions of the HH objects (see Fig. 1) suggest the stellar wind is interacting with the molecular fingers. If this interpretation is correct, the influence of the molecular outflow in Orion on the surrounding molecular clouds must be revised.

Highly Collimated, High Velocity Gas in the Orion B Molecular Outflow

1990 ◽  
pp. 289-290
Author(s):  
John Richer ◽  
Richard Hills ◽  
Rachael Padman ◽  
Paul Scott ◽  
Adrian Russell
Keyword(s):  
High Velocity ◽  
Molecular Outflow

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 Spatio-kinematical model of the collimated molecular outflow in the water-fountain nebula IRAS 16342–3814

2019 ◽  
Vol 629 ◽  
pp. A8 ◽  
Author(s):  
D. Tafoya ◽  
G. Orosz ◽  
W. H. T. Vlemmings ◽  
R. Sahai ◽  
A. F. Pérez-Sánchez
Keyword(s):  
Velocity Field ◽  
High Velocity ◽  
Three Dimensional ◽  
Opening Angle ◽  
Molecular Gas ◽  
Lower Velocity ◽  
Maser Emission ◽  
Molecular Outflow ◽  
Kinematical Model ◽  
Water Maser

Context. Water-fountain nebulae are asymptotic giant branch (AGB) and post-AGB objects that exhibit high-velocity outflows traced by water-maser emission. Their study is important for understanding the interaction between collimated jets and the circumstellar material that leads to the formation of bipolar and/or multi-polar morphologies in evolved stars. Aims. The aim of this paper is to describe the three-dimensional morphology and kinematics of the molecular gas of the water-fountain nebula IRAS 16342−3814. Methods. Data was retrieved from the ALMA archive for analysis using a simple spatio-kinematical model. The software SHAPE was employed to construct a three-dimensional, spatio-kinematical model of the molecular gas in IRAS 16342−3814, and to then reproduce the intensity distribution and position-velocity diagram of the CO emission from the ALMA observations to derive the morphology and velocity field of the gas. Data from CO(J = 1 → 0) supported the physical interpretation of the model. Results. A spatio-kinematical model that includes a high-velocity collimated outflow embedded within material expanding at relatively lower velocity reproduces the images and position-velocity diagrams from the observations. The derived morphology is in good agreement with previous results from IR and water-maser emission observations. The high-velocity collimated outflow exhibits deceleration across its length, while the velocity of the surrounding component increases with distance. The morphology of the emitting region, the velocity field, and the mass of the gas as function of velocity are in excellent agreement with the properties predicted for a molecular outflow driven by a jet. The timescale of the molecular outflow is estimated to be ~70–100 yr. The scalar momentum carried by the outflow is much larger than it can be provided by the radiation of the central star. An oscillating pattern was found associated with the high-velocity collimated outflow. The oscillation period of the pattern is T ≈ 60–90 yr and its opening angle is θop ≈ 2°. Conclusions. The CO (J = 3 → 2) emission in IRAS 16342−3814 is interpreted in terms of a jet-driven molecular outflow expanding along an elongated region. The position-velocity diagram and the mass spectrum reveal a feature due to entrained material that is associated with the driving jet. This feature is not seen in other more evolved objects that exhibit more developed bipolar morphologies. It is likely that the jet in those objects has already disappeared since it is expected to last only for a couple hundred years. This strengthens the idea that water fountain nebulae are undergoing a very short transition during which they develop the collimated outflows that shape the circumstellar envelopes. The oscillating pattern seen in the CO high-velocity outflow is interpreted as due to precession with a relatively small opening angle. The precession period is compatible with the period of the corkscrew pattern seen at IR wavelengths. We propose that the high-velocity molecular outflow traces the underlying primary jet that produces such a pattern.

scholarly journals Origin of High Velocity Pulsar and Soft Gamma Ray Repeaters

1996 ◽  
Vol 160 ◽  
pp. 359-360
Author(s):  
Hitoshi Hanami
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
High Velocity ◽  
Relative Velocity ◽  
Gamma Ray ◽  
Center Of Mass ◽  
Supernova Explosion ◽  
Close Binary System ◽  
Close Binary ◽  
X Ray

AbstractWe consider a close binary system with separation ≃ 0.2 R⊙which consists of a (C+O) star of mass ≃ 4 M⊙and a neutron star as a progenitor of soft gamma-ray repeater (SGR) and a high velocity pulsar. After the event of the supernova explosion, both new and old neutron stars have high relative velocity of ≃ 1000km s−1to the center of mass of the ejecta. SGR activities can be induced by the episodic accretion of the supernova ejecta onto the old neutron star or the strange high rotating pulsar of the new neutron star. Future observations with fine positional resolution can clarify the position ambiguity between the gamma ray and X-ray sources.

scholarly journals The Nature of the High Velocity Flow in CRL 618

1993 ◽  
Vol 155 ◽  
pp. 347-347
Author(s):  
R. Neri ◽  
M. Guélin ◽  
S. Guilloteau ◽  
R. Lucas ◽  
S. Garcia-Burillo ◽  
...  
Keyword(s):  
High Velocity ◽  
Planetary Nebula ◽  
Line Emission ◽  
Molecular Flow ◽  
Stellar Winds ◽  
Circumstellar Envelope ◽  
Hii Region ◽  
Molecular Outflow ◽  
Neutral Gas ◽  
Velocity Flow

Using the IRAM interferometer, we have mapped with a 2″.4 = 3″.4 resolution the J = 1 → 0 HCN line emission in the proto–planetary nebula CRL 618. Our maps resolve the 200 kms−1 molecular outflow (Cernicharo et al. 1989), as well as the slowly expanding circumstellar envelope (Bujarrabal et al. 1988), allowing a very precise positioning (≤ 0″.1) of these components with respect to the central HII region. 70% of the HCN envelope emission comes from a very compact, spherically symmetric core of size ≃ 3″.2. The core surrounds the high velocity gas which appears localized in a number of small ‘clumps’ (≤ 0″.5) – see figure. The large range of velocities observed in the ‘clumps’ suggests that we are not observing a decelerating molecular flow, but the impacts of a bipolar outflow on the slowly moving core, close to the HII region. The collision of a neutral gas outflow with high density regions (the ‘clumps’) results in the generation of dissociative shock-waves pushing and tearing the inner surface of the envelope. CRL 618 appears to have reached the stage where the stellar winds begin to disrupt and to scrape through the massive envelope, shortly before it evolves towards a Planetary Nebula.

A new high-velocity molecular outflow of IRAS 19282+1814

2003 ◽  
Vol 27 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Sun Ke-feng ◽  
Wu Yue-fang
Keyword(s):  
High Velocity ◽  
Molecular Outflow
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