Mass-loss rates, ionization fractions, shock velocities, and magnetic fields of stellar jets

Hartigan, Patrick; Morse, Jon A.; Raymond, John R.

doi:10.1086/174887

Cited by 241 publications

(313 citation statements)

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“…Similarly, the Hα/Hβ line ratios follow the predictions from the Hartigan et al (1994) shock models for the observed range in shock (see Sect. 3.2.3).…”

Section: Extinctionsupporting

confidence: 68%

“…Conditions may vary significantly between the regions up-and downstream of the shock front ("pre"-and "post"-shock, respectively; Hartigan et al 1994). The physical conditions of the shocked gas in the knots (post-shock electron density and total density, n e,post , n H,post ; temperature, T e ; and ionization, X e ) can be estimated by comparing observed line ratios with those predicted by collisional excitation models (Bacciotti & Eislöffel 1999; for an application to X-shooter spectra see e.g., Ellerbroek et al 2013).…”

Section: Physical Conditionsmentioning

confidence: 99%

“…The physical conditions of the shocked gas in the knots (post-shock electron density and total density, n e,post , n H,post ; temperature, T e ; and ionization, X e ) can be estimated by comparing observed line ratios with those predicted by collisional excitation models (Bacciotti & Eislöffel 1999; for an application to X-shooter spectra see e.g., Ellerbroek et al 2013). Similarly, the pre-shock parameters (shock velocity, shock ; pre-shock density n H,pre ; and magnetic field, B) can be obtained by comparing line ratios to shock models (e.g., Hartigan et al 1994).…”

Section: Physical Conditionsmentioning

confidence: 99%

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Relating jet structure to photometric variability: the Herbig Ae star HD 163296

Ellerbroek

Podio

Dougados

et al. 2014

A&A

131

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Herbig Ae/Be stars are intermediate-mass pre-main sequence stars surrounded by circumstellar dust disks. Some are observed to produce jets, whose appearance as a sequence of shock fronts (knots) suggests a past episodic outflow variability. This "jet fossil record" can be used to reconstruct the outflow history. We present the first optical to near-infrared (NIR) spectra of the jet from the Herbig Ae star HD 163296, obtained with VLT/X-shooter. We determine the physical conditions in the knots and also their kinematic "launch epochs". Knots are formed simultaneously on either side of the disk, with a regular interval of ∼16 yr. The velocity dispersion versus jet velocity and the energy input are comparable between both lobes. However, the mass-loss rate, velocity, and shock conditions are asymmetric. We findṀ jet /Ṁ acc ∼ 0.01−0.1, which is consistent with magneto-centrifugal jet launching models. No evidence of any dust is found in the high-velocity jet, suggesting a launch region within the sublimation radius (<0.5 au). The jet inclination measured from proper motions and radial velocities confirms that it is perpendicular to the disk. A tentative relation is found between the structure of the jet and the photometric variability of the central source. Episodes of NIR brightening were previously detected and attributed to a dusty disk wind. We report for the first time significant optical fadings lasting from a few days up to a year, coinciding with the NIR brightenings. These are very likely caused by dust lifted high above the disk plane, and this supports the disk wind scenario. The disk wind is launched at a larger radius than the high-velocity atomic jet, although their outflow variability may have a common origin. No significant relation between outflow and accretion variability could be established. Our findings confirm that this source undergoes periodic ejection events, which may be coupled with dust ejections above the disk plane.

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“…Similarly, the Hα/Hβ line ratios follow the predictions from the Hartigan et al (1994) shock models for the observed range in shock (see Sect. 3.2.3).…”

Section: Extinctionsupporting

confidence: 68%

Section: Physical Conditionsmentioning

confidence: 99%

Section: Physical Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Relating jet structure to photometric variability: the Herbig Ae star HD 163296

Ellerbroek

Podio

Dougados

et al. 2014

A&A

131

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“…Assuming the low-preshock density case of Hartigan et al (1994) a value of 60 ± 10 km s −1 was derived. Figure 1 shows faint bended Hα emission north of HH 892.…”

Section: The Herbig-haro Flowmentioning

confidence: 99%

The new nebula in LDN 1415 – A cry from the cradle of a low-luminosity source

Stecklum¹,

Melnikov

Meusinger³

2006

A&A

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Aims.A survey for candidate Herbig-Haro objects was performed to search for evidence of star formation in Galactic dark clouds Methods. For this aim true colour images were created from blue, red, and infrared DSS2 plates and inspected. Follow-up I-band, Hα, and [S ii] CCD imaging as well as long-slit spectroscopy using the Tautenburg 2-m telescope was carried out to verify candidate objects.Results. In the case of LDN 1415, the presence of a Herbig-Haro flow could be revealed which is henceforth named HH 892. In addition, an arcuate nebula was found which is barely seen on the DSS2 infrared plate (epoch 1996) and not detected in archival Kiso Schmidt data (epoch 2001). Thus, this nebula must have brightened by about 3.8 mag in recent years. Conclusions. The nebula is associated with IRAS 04376+5413. The 2MASS images show a red counterpart of the IRAS source, designated as L1415-IRS. Its morphology resembles that of a bipolar young object. The luminosity of this source integrated from 0.9 µm to 60 µm in the low state amounts to 0.13 L for an assumed distance of 170 pc. Thus it seems to be a young very-low mass star or it might even be of substellar mass. The current brightness increase of the nebula is caused by a FUor-or EXor-like outburst as indicated by the presence of a P Cygni profile of the Hα line. L1415-IRS is by far the least luminous member of the sparse sample of FUor and EXor objects.

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“…Important work by Raga (1991) and Hartigan et al (1994) demonstrated that HH jets were denser and hence more powerful than initial estimates suggested (e.g. Mundt et al 1987), so that the total momentum flux in HH jets integrated over the lifetime of a typical source is sufficient to drive the observed CO flows (e.g.…”

Section: Outflow Structurementioning

confidence: 99%

Molecular Outflows from Young Stellar Objects

Cabrit¹

1993

Astrophysics and Space Science Library

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We review some aspects of the bipolar molecular outflow phenomenon. In particular, we compare the morphological properties, energetics and velocity structures of outflows from high and low-mass protostars and investigate to what extent a common source model can explain outflows from sources of very different luminosities. Many flow properties, in particular the CO spatial and velocity structure, are broadly similar across the entire luminosity range, although the evidence for jet-entrainment is still less clear cut in massive flows than in low-mass systems. We use the correlation of flow momentum deposition rate with source luminosity to estimate the ratio f of mass ejection to mass accretion rate. From this analysis, it appears that a common driving mechanism could operate across the entire luminosity range. However, we stress that for the high-mass YSOs, the detailed physics of this mechanism and how the ejected wind/jet entrains ambient material remain to be addressed. We also briefly consider the alternative possibility that high-mass outflows can be explained by the recently proposed circulation models, and discuss several shortcomings of those models. Finally, we survey the current evidence on the nature of the shocks driven by YSOs during their pre-main-sequence evolution.

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Mass-loss rates, ionization fractions, shock velocities, and magnetic fields of stellar jets

Cited by 241 publications

References 0 publications

Relating jet structure to photometric variability: the Herbig Ae star HD 163296

Relating jet structure to photometric variability: the Herbig Ae star HD 163296

The new nebula in LDN 1415 – A cry from the cradle of a low-luminosity source

Molecular Outflows from Young Stellar Objects

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