Collimated molecular jets from high-mass young stars: IRAS 18151-1208

Davis, C. J.; Varricatt, W. P.; Todd, Stephen; Ramsay, Suzanne

doi:10.1051/0004-6361:20041298

Cited by 75 publications

(107 citation statements)

References 55 publications

(70 reference statements)

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“…They are very similar to those measured in other high-mass protostellar jets (10 18 -10 19 cm −2 ) (see e.g. Davis et al 2004;Gredel 2006), and they are 1-2 orders of magnitude higher than the values observed in low-mass jets.…”

Section: Ro-vibrational Diagrams From Nir Linessupporting

confidence: 87%

“…By varying the extinction value (A v ) and increasing the goodness of the fit (maximising the correlation coefficient), extinction and temperature can be evaluated simultaneously (see e.g. Giannini et al 2004;Davis et al 2004;Caratti o Garatti et al 2006). To reduce the uncertainties, only the transitions with S /N > 3 and not affected by blending with other lines were used.…”

Section: Ro-vibrational Diagrams From Nir Linesmentioning

confidence: 99%

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Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet

Garatti

Froebrich

Eisloeffel

et al. 2008

A&A

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Context. Protostellar jets from intermediate-and high-mass protostars provide an excellent opportunity to understand the mechanisms responsible for intermediate-and high-mass star-formation. A crucial question is if they are scaled-up versions of their low-mass counterparts. Such high-mass jets are relatively rare and, usually, they are distant and highly embedded in their parental clouds. The IRAS 20126+4104 molecular jet, driven by a 10 4 L protostar, represents a suitable target to investigate. Aims. We present here an extensive analysis of this protostellar jet, deriving the kinematical, dynamical, and physical conditions of the H 2 gas along the flow. Methods. The jet was investigated by means of near-IR H 2 and [Fe ii] narrow-band imaging, high-resolution spectroscopy of the 1-0 S(1) line (2.12 μm), NIR (0.9-2.5 μm) low-resolution spectroscopy, along with ISO-SWS and LWS spectra (from 2.4 to 200 μm). Results. The flow shows a complex morphology. In addition to the large-scale jet precession presented in previous studies, we detect a small-scale wiggling close to the source, which may indicate the presence of a multiple system. The peak radial velocities of the H 2 knots range from -42 to -14 km s −1 in the blue lobe, and from -8 to 47 km s −1 in the red lobe. The low-resolution spectra are rich in gas component has an average excitation temperature that ranges between 2000 K and 2500 K. Additionally, the ISO-SWS spectrum reveals a cold component (520 K) that strongly contributes to the radiative cooling of the flow and plays a major role in the dynamics of the flow. The estimated L H 2 of the jet is 8.2 ± 0.7 L , suggesting that IRAS 20126+4104 has a significantly increased accretion rate compared to low-mass YSOs. This is also supported by the derived mass flux rate from the H 2 lines (Ṁ out (H 2 ) ∼ 7.5 × 10 −4 M yr −1 ). The comparison between the H 2 and the outflow parameters strongly indicates that the jet is driving the outflow, at least partially. As already found for low-mass protostellar jets, the measured H 2 outflow luminosity is tightly related to the source bolometric luminosity. Conclusions. As for a few other intermediate-and high-mass protostellar jets in the literature, we conclude that IRAS 20126+4104 jet is a scaled-up version of low-mass protostellar counterparts.

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Section: Ro-vibrational Diagrams From Nir Linessupporting

confidence: 87%

Section: Ro-vibrational Diagrams From Nir Linesmentioning

confidence: 99%

Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet

Garatti

Froebrich

Eisloeffel

et al. 2008

A&A

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“…However, if one plots column densities derived from lines from only the first few vibrational states, a linear fit is usually quite adequate (e.g. Lorenzetti et al 2002;Giannini et al 2004;Davis et al 2004;Gredel 2006;Caratti o Garatti et al 2008;Martín-Hernández et al 2008). By minimising the scatter of points about this line, one can then estimate the extinction.…”

Section: Appendix A: the Effects Of Differential Refraction On Sourcementioning

confidence: 99%

VLT integral field spectroscopy of embedded protostars: using near-infrared emission lines as tracers of accretion and outflow

Davis

Cervantes

Nisini

et al. 2011

A&A

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Aims. We present near-infrared spectroscopy of the forbidden emission line (FEL) and molecular hydrogen emission line (MHEL) regions at the bases of Herbig-Haro (HH) jets from seven embedded protostars: SVS 13 (the HH 7-11 progenitor), HH 26-IRS, HH 34-IRS, HH 72-IRS, HH 83-IRS, HH 300-IRS (IRAS 04239+2436) and HH 999-IRS (IRAS 06047-1117) Methods. The integral field spectrograph, SINFONI, on the European Southern Observatory's Very Large Telescope (VLT) was used to characterise jet parameters in these formative regions, where the jets are collimated and accelerated. Results. We find considerable differences in the spectra of HH 83-IRS when compared to the other six sources; CO bandhead and atomic permitted lines from Ca i, Na i, Mg i and Al i are observed in emission in all but HH 83-IRS, where they are detected in absorption. It is likely that this source is more evolved than the others (or at the very least considerably less active). Strong CO bandhead emission is also detected in emission in the other six sources, while extended H 2 ro-vibrational and [Fe ii] forbidden emission lines trace the outflows (only the HH jet from HH 83-IRS is undetected). CO bandhead and Brγ emission peaks are in most cases coincident with the jet source continuum position, consistent with excitation in an accretion disk or accretion flow. However, in the closest source, HH 300-IRS, we do find evidence for excitation in the outflow: here the emission peak is offset by 3.6(±0.7) AU along the flow axis. We also note a correlation between CO and Mg i, Na i and Ca i intensities, which supports the idea that these atomic permitted lines are associated with accretion disks. From H 2 and [Fe ii] images we measure jet widths and derive upper limits to flow component opening angles. Although we do not find that the ionised [Fe ii] component is consistently narrower than the H 2 flow component, we do find that narrower H 2 and/or [Fe ii] flow components are associated with higher radial velocities (as reported in the literature). Flow opening angles, over the first few hundred AU in each source, are measured to be in the range 21 • -42 • in both H 2 and [Fe ii]. Finally, from our 3-D data we are also able to map the extinction and electron density at the base of the outflows from some of our targets: within a few hundred AU, both decrease sharply with distance from the source. Conclusions. It seems clear that collimated atomic and molecular jets, which may initially exhibit a wide opening angle, are a feature of outflows from Class I protostars, Class II T Tauri stars, and possibly even Class 0 sources, and that these jets can be traced to within a few hundred AU of the driving source. A common jet collimation and acceleration mechanism seems inescapable for all stages of low mass star formation.

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“…Although the calculated momentum rate in the SiO jet is adequate to power the CO flow, the uncertainties in the assumed SiO abundance makes this difficult to prove. Another example is IRAS 18151-1208 in which the H 2 jet appears to have adequate momentum to power the observed CO flow (Beuther et al 2002a, Davis et al 2004. For sources that have a weak jet component coupled with a wide-angle flow, it has not been determined what fraction of the momentum rate is supplied by the jet.…”

Section: Outflow Energeticsmentioning

confidence: 99%

Massive star outflows

Shepherd¹

2005

Proc. IAU

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Abstract. Molecular outflows in the form of wide-angle winds and/or well-collimated jets are associated with young stellar objects of all luminosities. Independent studies have established that the mass outflow rate is proportional to L 0. 6 bo l for L bo l = 0.3 to 10 5 L , suggesting that there is a strong link between accretion and outflow for a wide range of source luminosity and there is reasonable evidence that accretion-related processes are responsible for generating massive molecular flows from protostars up to spectral type B0. Beyond L bo l ∼ 10 4 L , O stars generate powerful wide-angle, ionized winds that can dramatically affect outflow morphology and even call into question the relationship between outflow and accretion.Recently Beuther & Shepherd 2005 have proposed an evolutionary scenario in which massive protostellar flows (up to early B spectral type) begin collimated. Once the star reaches the Main Sequence, ionizing radiation may affect the balance between magnetic and plasma pressure, inducing changes in the flow morphology and energetics. Here I review the properties of outflows from young OB stars, discuss implications and observational tests of this proposed evolutionary scenario, and examine differences between low-mass and massive star formation.

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Collimated molecular jets from high-mass young stars: IRAS 18151-1208

Cited by 75 publications

References 55 publications

Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet

Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet

VLT integral field spectroscopy of embedded protostars: using near-infrared emission lines as tracers of accretion and outflow

Massive star outflows

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