Ionization driven molecular outflow in K3-50A

Klaassen, Pamela; Galván-Madrid, Roberto; Peters, Thomas; Longmore, Steven N.; Maercker, M.

doi:10.1051/0004-6361/201219683

Cited by 8 publications

(8 citation statements)

References 28 publications

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“…From the CO data, we calculate a velocity gradient of 155 km s −1 pc −1 . This value is comparable to molecular outflow velocities seen in other high mass sources, such as K3-50A (Klaassen et al 2013).…”

Section: Jet-like Properties In Outflow Asupporting

confidence: 83%

Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335

Avison

Fuller

Peretto

et al. 2021

A&A

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Context. The infrared dark cloud (IRDC) SDC335.579-0.292 (hereafter, SDC335) is a massive (~5000 M⊙) star-forming cloud which has been found to be globally collapsing towards one of the most massive star forming cores in the Galaxy, which is located at its centre. SDC335 is known to host three high-mass protostellar objects at early stages of their evolution and archival ALMA Cycle 0 data (at ~5′′ resolution) indicate the presence of at least one molecular outflow in the region detected in HNC. Observations of molecular outflows from massive protostellar objects allow us to estimate the accretion rates of the protostars as well as to assess the disruptive impact that stars have on their natal clouds during their formation. Aims. The aim of this work is to identify and analyse the properties of the protostellar-driven molecular outflows within SDC335 and use these outflows to help refine the properties of the young massive protostars in this cloud. Methods. We imaged the molecular outflows in SDC335 using new data from the Australia Telescope Compact Array of SiO and Class I CH3OH maser emission (at a resolution of ~3′′) alongside observations of four CO transitions made with the Atacama Pathfinder EXperiment and archival Atacama Large Millimeter/submillimeter Array (ALMA) CO, 13CO (~1′′), and HNC data. We introduced a generalised argument to constrain outflow inclination angles based on observed outflow properties. We then used the properties of each outflow to infer the accretion rates on the protostellar sources driving them. These accretion properties allowed us to deduce the evolutionary characteristics of the sources. Shock-tracing SiO emission and CH3OH Class I maser emission allowed us to locate regions of interaction between the outflows and material infalling to the central region via the filamentary arms of SDC335. Results. We identify three molecular outflows in SDC335 – one associated with each of the known compact H II regions in the IRDC. These outflows have velocity ranges of ~10 km s−1 and temperatures of ~60 K. The two most massive sources (separated by ~9000 AU) have outflows with axes which are, in projection, perpendicular. A well-collimated jet-like structure with a velocity gradient of ~155 km s−1 pc−1 is detected in the lobes of one of the outflows. The outflow properties show that the SDC335 protostars are in the early stages (Class 0) of their evolution, with the potential to form stars in excess of 50 M⊙. The measured total accretion rate, inferred from the outflows, onto the protostars is 1.4(±0.1) × 10−3 M⊙ yr−1, which is comparable to the total mass infall rate toward the cloud centre on parsec scales of 2.5(±1.0) × 10−3 M⊙ yr−1, suggesting a near-continuous flow of material from cloud to core scales. Finally, we identify multiple regions where the outflows interact with the infalling material in the cloud’s six filamentary arms, creating shocked regions and pumping Class I methanol maser emission. These regions provide useful case studies for future investigations of the disruptive effect of young massive stars on their natal clouds.

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Section: Jet-like Properties In Outflow Asupporting

confidence: 83%

Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335

Avison

Fuller

Peretto

et al. 2021

A&A

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“…This picture is supported by analytic and numeric models with Keplerian disks growing with time from the infalling rotating structure (e.g., Stahler & Palla 2005;Kuiper et al 2011). The transition from molecular to ionized infall is an additional important characteristic (e.g., Keto 2002Keto , 2003Klaassen et al 2009Klaassen et al , 2013. While indirect evidence for massive disks is very strong, direct observations are still sparse (see AFGL4176 as one of the best recent examples; Johnston et al 2015, of G11.92-0.61 by Ilee et al 2016).…”

Section: Introductionmentioning

confidence: 84%

Multiplicity and disks within the high-mass core NGC 7538IRS1

Beuther

Linz

Henning

et al. 2017

A&A

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Context. High-mass stars have a high degree of multiplicity and most likely form via disk accretion processes. The detailed physics of the binary and disk formation are still poorly constrained. Aims. We seek to resolve the central substructures of the prototypical high-mass star-forming region NGC7538IRS1 at the highest possible spatial resolution line and continuum emission to investigate the protostellar environment and kinematics. Methods. Using the Karl G. Jansky Very Large Array (VLA) in its most extended configuration at ∼24 GHz has allowed us to study the NH 3 and thermal CH 3 OH emission and absorption as well as the cm continuum emission at an unprecedented spatial resolution of 0.06 × 0.05 , corresponding to a linear resolution of ∼150 AU at a distance of 2.7 kpc. Results. A comparison of these new cm continuum data with previous VLA observations from 23 yrs ago reveals no recognizable proper motions. If the emission were caused by a protostellar jet, proper motion signatures should have been easily identified. In combination with the high spectral indices S ∝ ν α (α between 1 and 2), this allows us to conclude that the continuum emission is from two hypercompact Hii regions separated in projection by about 430 AU. The NH 3 spectral line data reveal a common rotating envelope indicating a bound high-mass binary system. In addition to this, the thermal CH 3 OH data show two separate velocity gradients across the two hypercompact Hii regions. This indicates two disk-like structures within the same rotating circumbinary envelope. Disk and envelope structures are inclined by ∼33• , which can be explained by initially varying angular momentum distributions within the natal, turbulent cloud. Conclusions. Studying high-mass star formation at sub-0.1 resolution allows us to isolate multiple sources as well as to separate circumbinary from disk-like rotating structures. These data show also the limitations in molecular line studies in investigating the disk kinematics when the central source is already ionizing a hypercompact Hii region. Recombination line studies will be required for sources such as NGC7538IRS1 to investigate the gas kinematics even closer to the protostars.

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“…For example, Araya et al (2005), who used single-pointing 15 m SEST (Swedish-ESO Submillimetre Telescope) telescope observations, detected H41α line emission in nine sites of high-mass star formation. More recently, Klaassen et al (2013) detected H41α towards the high-mass star-forming region K3-50A using the CARMA (Combined Array for Research in Millimetre-wave Astronomy) interferometer, and suggested that the line is tracing the outflow entrained by photoionised gas.…”

Section: H41αmentioning

confidence: 99%

A MALT90 study of the chemical properties of massive clumps and filaments of infrared dark clouds

Miettinen

2014

A&A

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Context. Infrared dark clouds (IRDCs) provide a useful testbed in which to investigate the genuine initial conditions and early stages of massive-star formation. Aims. We attempt to characterise the chemical properties of a sample of 35 massive clumps of IRDCs through multi-molecular line observations. We also search for possible evolutionary trends among the derived chemical parameters.Methods. The clumps are studied using the MALT90 (Millimetre Astronomy Legacy Team 90 GHz) line survey data obtained with the Mopra 22 m telescope. The survey covers 16 different transitions near 90 GHz. The spectral-line data are used in concert with our previous LABOCA (Large APEX BOlometer CAmera) 870 μm dust emission data. Results. Eleven MALT90 transitions are detected towards the clumps at least at the 3σ level. Most of the detected species (SiO, C 2 H, HNCO, HCN, HCO + , HNC, HC 3 N, and N 2 H + ) show spatially extended emission towards many of the sources. Most of the fractional abundances of the molecules with respect to H 2 are found to be comparable to those determined in other recent similar studies of IRDC clumps. We found that the abundances of SiO, HNCO, and HCO + are higher in IR-bright clumps than in IR-dark sources, reflecting a possible evolutionary trend. A hint of this trend is also seen for HNC and HC 3 N. An opposite trend is seen for the C 2 H and N 2 H + abundances. Moreover, a positive correlation is found between the abundances of HCO + and HNC, and between those of HNC and HCN. The HCN and HNC abundances also appear to increase as a function of the N 2 H + abundance. The HNC/HCN and N 2 H + /HNC abundance ratios are derived to be near unity on average, while that of HC 3 N/HCN is ∼10%. The N 2 H + /HNC ratio appears to increase as the clump evolves, while the HNC/HCO + ratio shows the opposite behaviour. Conclusions. The detected SiO emission is probably caused by shocks driven by outflows in most cases, although shocks resulting from the cloud formation process could also play a role. Shock-origin for the HNCO, HC 3 N, and CH 3 CN emission is also plausible. The average HNC/HCN ratio is in good agreement with those seen in other IRDCs, but gas temperature measurements would be neeeded to study its temperature dependence. Our results support the finding that C 2 H can trace the cold gas, and not just the photodissociation regions. The HC 3 N/HCN ratio appears to be comparable to the values seen in other types of objects, such as T Tauri disks and comets.

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Ionization driven molecular outflow in K3-50A

Cited by 8 publications

References 28 publications

Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335

Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335

Multiplicity and disks within the high-mass core NGC 7538IRS1

A MALT90 study of the chemical properties of massive clumps and filaments of infrared dark clouds

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