Herbig‐Haro Jets from Orbiting Sources

Masciadri, E.; Raga, A. C.

doi:10.1086/338767

Cited by 73 publications

(98 citation statements)

References 36 publications

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“…Part of this effect may be contaminated by multiple outflows (e.g., in outflow SMA2a). Nevertheless, the mirror symmetric (C-shaped) wiggles and point symmetric (S-shaped) wiggles may indicate different bending mechanisms like jet precession, orbital motion of the jet source, and Lorentz forces (Fendt & Zinnecker 1998;Masciadri & Raga 2002;Raga et al 2009). Similar bending effects have been observed in a number of Herbig-Haro jets (e.g., HH 211, Lee et al 2010) and some of the most collimated high-mass molecular jets (e.g., Su et al 2007).…”

Section: Spectral Line Data and Co Outflows 321 Morphologymentioning

confidence: 99%

Hierarchical Fragmentation and Jet-Like Outflows in Irdc G28.34+0.06: A Growing Massive Protostar Cluster

Wang

Zhang

et al. 2011

ApJ

149

210

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We present Submillimeter Array (SMA) λ = 0.88 mm observations of an infrared dark cloud G28.34+0.06. Located in the quiescent southern part of the G28.34 cloud, the region of interest is a massive (>10 3 M ) molecular clump P1 with a luminosity of ∼10 3 L , where our previous SMA observations at 1.3 mm have revealed a string of five dust cores of 22-64 M along the 1 pc IR-dark filament. The cores are well aligned at a position angle (P.A.) of 48• and regularly spaced at an average projected separation of 0.16 pc. The new high-resolution, high-sensitivity 0.88 mm image further resolves the five cores into 10 compact condensations of 1.4-10.6 M , with sizes of a few thousand AU. The spatial structure at clump (∼1 pc) and core (∼0.1 pc) scales indicates a hierarchical fragmentation. While the clump fragmentation is consistent with a cylindrical collapse, the observed fragment masses are much larger than the expected thermal Jeans masses. All the cores are driving CO (3-2) outflows up to 38 km s −1 , the majority of which are bipolar, jet-like outflows. The moderate luminosity of the P1 clump sets a limit on the mass of protostars of 3-7 M . Because of the large reservoir of dense molecular gas in the immediate medium and ongoing accretion as evident by the jet-like outflows, we speculate that P1 will grow and eventually form a massive star cluster. This study provides a first glimpse of massive, clustered star formation that currently undergoes through an intermediate-mass stage.

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Section: Spectral Line Data and Co Outflows 321 Morphologymentioning

confidence: 99%

Hierarchical Fragmentation and Jet-Like Outflows in Irdc G28.34+0.06: A Growing Massive Protostar Cluster

Wang

Zhang

et al. 2011

ApJ

149

210

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“…The precession period is generally at least one order of magnitude larger than the orbital period. Therefore, to justify such a large p , we need a value of the ratio between the accretion radius disk R and the orbital radius r 0 ( ¼ R=r 0 ) of the order of 10 À3 (see Masciadri & Raga 2002). Reipurth (2000) has also proposed that perturbations on an accretion disk due to close passages (i.e., at perihelion) of a binary companion in an elliptical orbit could be responsible for producing a time variability in the ejection of the outflow.…”

Section: Introductionmentioning

confidence: 99%

The Precession of the Giant HH 34 Outflow: A Possible Jet Deceleration Mechanism

Masciadri

Pino

Raga

et al. 2002

ApJ

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The giant jets represent a fundamental trace of the historical evolution of the outflow activity over timescales of $10 4 yr, i.e., a timescale comparable to the accretion time of the outflow sources in their main protostellar phase. The study of such huge jets provides the possibility of retrieving important elements related to the life of the outflow sources. In this paper, we study the role of precession (combined with jet velocity variability and the resulting enhanced interaction with the surrounding environment) as a deceleration mechanism for giant jets, using a numerical approach. This thesis was proposed for the first time by Devine et al., but it could not be numerically explored until now, because it is intrinsically difficult to reproduce, at the same time, the large range of scales from $100 AU up to a few parsecs. In the present paper, we obtain predictions of H intensity maps and position-velocity diagrams from three-dimensional simulations of the giant HH 34 jet (including an appropriate ejection velocity time variability and a precession of the outflow axis), and we compare them with previously published observations of this object. Our simulations represent a step forward from previous numerical studies of HH objects, in that the use of a seven-level, binary adaptive grid has allowed us to compute models that appropriately cover all relevant scales of a giant jet, from the $100 AU jet radius close to the source to the $1 pc length of the outflow. A good qualitative and quantitative agreement is found between the model predictions and the observations, indicating that a precession of the jet axis can indeed be the probable cause of the deceleration of the giant jets. Moreover, we show that a critical parameter for obtaining a better or worse agreement with the observations is the ratio j = a between the jet and the environmental densities. The implications of this result in the context of the current star formation models are discussed.

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“…As we have pointed out in the past (Masciadri & Raga 2002;Raga et al 2009), an orbital motion of the jet source can result in mirror symmetries of the outflow lobes. However, the relatively low orbital velocities possible for the sources of observed mirror-symmetric pPNs cannot be responsible for the large angular deviations of their outflow lobes (Velázquez et al 2013;Riera et al 2014).…”

Section: Discussionmentioning

confidence: 79%

“…For orbital periods less than the precession period, these authors found that mirror symmetry is observed close to the central source with respect to the orbital plane, while point-symmetric morphologies prevail at larger distances (Masciadri & Raga 2002;Raga et al 2009). The influence of the orbital motion on the line emission of these objects was analyzed by Haro-Corzo et al (2009).…”

Section: Introductionmentioning

confidence: 98%

An Asymmetric Jet-Launching Model for the Protoplanetary Nebula CRL 618

Velázquez

Riera

Raga

et al. 2014

ApJ

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We propose an asymmetrical jet-ejection mechanism in order to model the mirror symmetry observed in the lobe distribution of some protoplanetary nebulae (pPNs), such as the pPN CRL 618. Three-dimensional hydrodynamical simulations of a precessing jet launched from an orbiting source were carried out, including an alternation in the ejections of the two outflow lobes, depending on which side of the precessing accretion disk is hit by the accretion column from a Roche lobe-filling binary companion. Both synthetic optical emission maps and position-velocity diagrams were obtained from the numerical results with the purpose of carrying out a direct comparison with observations. Depending on the observer's point of view, multipolar morphologies are obtained that exhibit a mirror symmetry at large distances from the central source. The obtained lobe sizes and their spatial distributions are in good agreement with the observed morphology of the pPN CRL 618. We also obtain that the kinematic ages of the fingers are similar to those obtained in the observations.

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Herbig‐Haro Jets from Orbiting Sources

Cited by 73 publications

References 36 publications

Hierarchical Fragmentation and Jet-Like Outflows in Irdc G28.34+0.06: A Growing Massive Protostar Cluster

Hierarchical Fragmentation and Jet-Like Outflows in Irdc G28.34+0.06: A Growing Massive Protostar Cluster

The Precession of the Giant HH 34 Outflow: A Possible Jet Deceleration Mechanism

An Asymmetric Jet-Launching Model for the Protoplanetary Nebula CRL 618

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