An unusual outflow around IRAS 16293-2422

Walker, Christopher K.; Lada, Charles J.; Young, Erick T.; Margulis, M.

doi:10.1086/166659

Cited by 69 publications

(50 citation statements)

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“…The emission is clearly resolved and shows a ∼6 separation between the red (4−7 km s −1 ) and blue (1−4 km s −1 ) emission peaks. The direction of the red-blue asymmetry is roughly perpendicular to the large scale CO outflow associated with MM1 (Walker et al 1988;Mizuno et al 1990;Stark et al 2004), and may be indicative of overall rotation of the circumbinary material encompassing both MM1 and MM2. The morphology and velocity structure is also consistent with a large (∼1000 AU diameter) rotating gaseous disk around just MM1, however.…”

Section: O Emissionmentioning

confidence: 93%

“…The frequency setting includes the 3 03 → 2 02 and 3 22 → 2 21 H 2 CO lines, whose ratio is a measure of the gas temperature of the circumstellar material. Both IRAS 16293-2422 and L1448-C are deeply embedded class 0 protostars (André et al 1993) which drive large scale (∼arcmin) bipolar outflows (Walker et al 1988;Mizuno et al 1990;Bachiller et al 1990Bachiller et al , 1991Stark et al 2004). For other low-mass objects, molecules such as SiO are clearly associated with the outflow (e.g., L1448: Guilloteau et al 1992; NGC 1333 IRAS4: Blake et al 1995), whereas optically thick lines from other species such as HCO + and HCN are found to "coat" the outflow walls (e.g., B5 IRS1: Langer et al 1996;L1527 and Serpens SMM1: Hogerheijde et al 1997.…”

Section: Introductionmentioning

confidence: 99%

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On the origin of H$_\mathsf{2}$CO abundance enhancements in low-mass protostars

Schöier

Jørgensen

Dishoeck

et al. 2004

A&A

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Abstract.High angular resolution H 2 CO 218 GHz line observations have been carried out toward the low-mass protostars IRAS 16293-2422 and L1448-C using the Owens Valley Millimeter Array at ∼2 resolution. Simultaneous 1.37 mm continuum data reveal extended emission which is compared with that predicted by model envelopes constrained from single-dish data. For L1448-C the model density structure works well down to the 400 AU scale to which the interferometer is sensitive. For IRAS 16293-2422, a known proto-binary object, the interferometer observations indicate that the binary has cleared much of the material in the inner part of the envelope, out to the binary separation of ∼800 AU. For both sources there is excess unresolved compact emission centered on the sources, most likely due to accretion disks < ∼ 200 AU in size with masses of IRAS 16293-2422). The H 2 CO data for both sources are dominated by emission from gas close to the positions of the continuum peaks. The morphology and velocity structure of the H 2 CO array data have been used to investigate whether the abundance enhancements inferred from single-dish modelling are due to thermal evaporation of ices or due to liberation of the ice mantles by shocks in the inner envelope. For IRAS 16293-2422 the H 2 CO interferometer observations indicate the presence of rotation roughly perpendicular to the large scale CO outflow. The H 2 CO distribution differs from that of C 18 O, with C 18 O emission peaking near MM1 and H 2 CO stronger near MM2. For L1448-C, the region of enhanced H 2 CO emission extends over a much larger scale >1 than the radius of 50−100 K (0. 6−0. 15) where thermal evaporation can occur. The red-blue asymmetry of the emission is consistent with the outflow; however the velocities are significantly lower. The H 2 CO 3 22 −2 21 /3 03 −2 02 flux ratio derived from the interferometer data is significantly higher than that found from single-dish observations for both objects, suggesting that the compact emission arises from warmer gas. Detailed radiative transfer modeling shows, however, that the ratio is affected by abundance gradients and optical depth in the 3 03 −2 02 line. It is concluded that a constant H 2 CO abundance throughout the envelope cannot fit the interferometer data of the two H 2 CO lines simultaneously on the longest and shortest baselines. A scenario in which the H 2 CO abundance drops in the cold dense part of the envelope where CO is frozen out but is undepleted in the outermost region provides good fits to the single-dish and interferometer data on short baselines for both sources. Emission on the longer baselines is best reproduced if the H 2 CO abundance is increased by about an order of magnitude from ∼10 −10 to ∼10 −9 in the inner parts of the envelope due to thermal evaporation when the temperature exceeds ∼50 K. The presence of additional H 2 CO abundance jumps in the innermost hot core region or in the disk cannot be firmly established, however, with the present sensitivity and resolution. Other scenarios, includi...

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Section: O Emissionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

On the origin of H$_\mathsf{2}$CO abundance enhancements in low-mass protostars

Schöier

Jørgensen

Dishoeck

et al. 2004

A&A

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“…CO line emission toward IRAS 16293-2422 show a characteristic quadrupolar structure (Walker et al 1988), which could reflect its binary nature. Stark et al (2004) suggested that this quadrupolar morphology could be interpreted as being a superposition of an older outflow in the East-West direction driven by A100, page 14 of 28 IRAS 16293B and a younger outflow in the Northeast/Southwest direction driven by IRAS 16293A.…”

Section: The Importance Of the Outflows In Iras 16293-2422mentioning

confidence: 96%

Arcsecond resolution images of the chemical structure of the low-mass protostar IRAS 16293-2422

Jørgensen

Bourke

Luong

et al. 2011

A&A

104

179

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It remains a key challenge to establish the molecular content of different components of low-mass protostars, like their envelopes and disks, and how this depends on the evolutionary stage and/or environment of the young stars. Observations at submillimeter wavelengths provide a direct possibility to study the chemical composition of low-mass protostars through transitions probing temperatures up to a few hundred K in the gas surrounding these sources. This paper presents a large molecular line survey of the deeply embedded protostellar binary IRAS 16293-2422 from the Submillimeter Array (SMA) -including images of individual lines down to ≈1.5−3 (190−380 AU) resolution. More than 500 individual transitions are identified related to 54 molecular species (including isotopologues) probing temperatures up to about 550 K. Strong chemical differences are found between the two components in the protostellar system with a separation between, in particular, the sulfur-and nitrogen-bearing species and oxygen-bearing complex organics. The action of protostellar outflow on the ambient envelope material is seen in images of CO and SiO and appear to influence a number of other species, including (deuterated) water, HDO. The effects of cold gas-phase chemistry is directly imaged through maps of CO, N 2 D + and DCO + , showing enhancements of first DCO + and subsequently N 2 D + in the outer envelope where CO freezes-out on dust grains.

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“…Indeed, I16293 is known to have a quadrupolar outflow (Walker et al 1988;Mizuno et al 1990;Castets et al 2001;Rao et al 2009) suggesting the existence of a binary system. However, significant physical differences (chemical and kinematic) exist, suggesting different natures or different evolutionary stages of the two continuum sources A and B.…”

Section: Introductionmentioning

confidence: 99%

The first ALMA view of IRAS 16293-2422

Pineda

Maury

Fuller

et al. 2012

A&A

120

164

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Aims. We focus on the kinematical properties of a proto-binary to study the infall and rotation of gas toward its two protostellar components. Methods. We present ALMA Science Verification observations with high-spectral resolution of IRAS 16293-2422 at 220.2 GHz. The wealth of molecular lines in this source and the very high spectral resolution offered by ALMA allow us to study the gas kinematics with unprecedented detail. Results. We present the first detection of an inverse P-Cygni profile toward source B in the three brightest lines. The line profiles are fitted with a simple two-layer model to derive an infall rate of 4.5 × 10 −5 M yr −1 . This infall detection would rule-out the previously suggested possibility that source B is a T Tauri star. A position velocity diagram for source A shows evidence of rotation with an axis close to the line-of-sight.

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An unusual outflow around IRAS 16293-2422

Cited by 69 publications

References 0 publications

On the origin of H$_\mathsf{2}$CO abundance enhancements in low-mass protostars

On the origin of H$_\mathsf{2}$CO abundance enhancements in low-mass protostars

Arcsecond resolution images of the chemical structure of the low-mass protostar IRAS 16293-2422

The first ALMA view of IRAS 16293-2422

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