Molecular outflows associated with bright far-infrared sources

Snell, R. L.; Huang, Y. L.; Dickman, R. L.; Claussen, M. J.

doi:10.1086/166056

Cited by 105 publications

(103 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We report a convincing signature of infall of a circumstellar molecular envelope with a radius of only 300 AU in the high-mass star-forming region AFGL 5142 (1.8 kpc; Snell et al 1988). Observations with the Submillimeter Array (SMA) at 1.3 mm identified a high-mass protocluster containing five dusty mm cores and three CO outflows within a few arcseconds of each other (Zhang et al 2007).…”

Section: Introductionmentioning

confidence: 84%

Infall and outflow within 400 AU from a high-mass protostar

Goddi

Moscadelli

Sanna

2011

A&A

View full text Add to dashboard Cite

Observational signatures of infalling envelopes and outflowing material in early stages of protostellar evolution and at small radii from the protostar are essential to progress in the understanding of the mass-accretion process in star formation. In this Letter, we report a detailed study on the accretion and outflow structure around a protostar in the well-known high-mass star-forming region AFGL 5142. We focus on the mm source MM-1, which exhibits hot-core chemistry, radio continuum emission, and strong water (H 2 O) and methanol (CH 3 OH) masers. Remarkably, our Very Long Baseline Interferometry (VLBI) observations of molecular masers over six years provided us with the 3D velocity field of circumstellar molecular gas with a resolution of 0.001-0.005 and at radii <0. 23 (or 400 AU) from the protostar. In particular, our measurements of CH 3 OH maser emission for the first time provided a direct measurement of the infall of a molecular envelope (radius of 300 AU and velocity of 5 km s −1 ) onto an intermediate-to high-mass protostar. We estimate an infall rate of 6 × 10 −4 n 8 M yr −1 , where n 8 is the ambient volume density in units of 10 8 cm −3 (required for maser excitation). In addition, our measurements of the H 2 O maser (and radio continuum) emission identify a collimated bipolar molecular outflow (and ionized jet) from MM-1. The evidence of simultaneous accretion and outflow at small spatial scales makes AFGL 5142 an extremely compelling target for high-angular resolution studies of high-mass star formation.

show abstract

Section: Introductionmentioning

confidence: 84%

Infall and outflow within 400 AU from a high-mass protostar

Goddi

Moscadelli

Sanna

2011

A&A

View full text Add to dashboard Cite

show abstract

“…The CH 3 OH masers show a linear distribution of 120 mas with a roughly linear velocity gradient along it, although a few masers following a different velocity distribution (Minier et al 2000). A CO-outflow (PA out = 130 • , Snell et al 1988;Wu et al 2010) is centered and perpendicular to the linear distribution of the CH 3 OH masers (Wu et al 2010). Wu et al (2010) measured a velocity range for the blue-shifted and red-shifted lobes of −10 km s −1 < V blue IRAS 06058 < −2 km s −1 and +8 km s −1 < V red IRAS 06058 < +20 km s −1 , respectively.…”

Section: Iras 06058+2138-nirsmentioning

confidence: 99%

EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions

Surcis

Vlemmings

Langevelde

et al. 2013

A&A

View full text Add to dashboard Cite

Context. Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields play an important role in the formation and dynamics of molecular outflows. Masers, in particular 6.7-GHz CH 3 OH masers, are the best probes of the magnetic field morphologies around massive young stellar objects on the smallest scales of 10-100 AU. Aims. Providing new observational measurements of the morphology of magnetic fields around massive young stellar objects by using 6.7-GHz CH 3 OH maser emission is very important for setting constraints on the numerical simulations of massive star formation. Methods. This paper focuses on 4 massive young stellar objects, IRAS 06058+2138-NIRS 1, IRAS 22272+6358A, S255-IR, and S231, which complement our previous 2012 sample (the first EVN group). From all these sources, molecular outflows have been detected in the past. Seven of the European VLBI Network antennas were used to measure the linear polarization and Zeeman-splitting of the 6.7-GHz CH 3 OH masers in the star-forming regions in this second EVN group. Results. We detected a total of 128 CH 3 OH masing cloudlets. Fractional linear polarization (0.8%-11.3%) was detected towards 18% of the CH 3 OH masers in our sample. The linear polarization vectors are well ordered in all the massive young stellar objects. We measured significant Zeeman-splitting in IRAS 06058+2138-NIRS 1 (ΔV Z = 3.8 ± 0.6 m s −1 ) and S255-IR (ΔV Z = 3.2 ± 0.7 m s −1 ). Conclusions. By considering the 20 massive young stellar objects towards which the morphology of magnetic fields was determined by observing 6.7-GHz CH 3 OH masers in both hemispheres, we find no evident correlation between the linear distributions of CH 3 OH masers and the outflows or the linear polarization vectors. On the other hand, we present first statistical evidence that the magnetic field (on scales 10-100 AU) is primarily oriented along the large-scale outflow direction. Moreover, we empirically find that the linear polarization fraction of unsaturated CH 3 OH masers is P l < 4.5%.

show abstract

“…GL 4029 IRS1 is located near the centre of a bipolar molecular outflow (Snell et al 1988). Both outflow lobes have their peak emission coincident with the IR source.…”

Section: Gl 4029 Irs1mentioning

confidence: 99%

“…• (Snell et al 1988). K-band imaging polarimetry shows a small cluster within extensive nebulosity (Tamura et al 1991;Yao et al 2000).…”

Section: Gl 5180 Irs1mentioning

confidence: 99%

Near-IR speckle imaging of massive young stellar objects

Álvarez

Hoare

Glindemann

et al. 2004

A&A

View full text Add to dashboard Cite

Abstract. We present near-IR speckle images of 21 massive Young Stellar Objects (YSOs) associated with outflows. The aim of this study is to search for sub-arcsecond reflection nebulae associated with the outflow cavity. We find that 6 of the massive YSOs show a conical nebula which can be interpreted in terms of reflected light from the dusty walls of the outflow cavity. In all cases, the small scale structures seen in our images are compared with outflow indicators found in the literature. No clear correlation is found between the presence of the reflection nebulosity and any property such as degree of embeddedness. We also note that 3 of the sources show close companions, one of them belonging also to the sample with conical nebula.

show abstract

Molecular outflows associated with bright far-infrared sources

Cited by 105 publications

References 0 publications

Infall and outflow within 400 AU from a high-mass protostar

Infall and outflow within 400 AU from a high-mass protostar

EVN observations of 6.7 GHz methanol maser polarization in massive star-forming regions

Near-IR speckle imaging of massive young stellar objects

Contact Info

Product

Resources

About