Nascent bipolar outflows associated with the first hydrostatic core candidates Barnard 1b-N and 1b-S

Gérin, M.; Pety, J.; Fuente, A.; Cernicharo, J.; Commerçon, B.; Marcelino, N.

doi:10.1051/0004-6361/201525777

Cited by 56 publications

(88 citation statements)

References 30 publications

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“…Even though their outflows suggest inclination misaglinment (Gerin et al 2015), the SEDs appear to be similar, indicating coevality, which is consistent with the results obtained from the analysis of their environment (Hirano & Liu 2014). The inclination misalignment may therefore be small.…”

Section: Outflowssupporting

confidence: 85%

Do siblings always form and evolve simultaneously? Testing the coevality of multiple protostellar systems through SEDs

Murillo

Dishoeck

Tobin

et al. 2016

A&A

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Context. Multiplicity is common in field stars and among protostellar systems. Models suggest two paths of formation: turbulent fragmentation and protostellar disk fragmentation. Aims. We attempt to find whether or not the coevality frequency of multiple protostellar systems can help to better understand their formation mechanism. The coevality frequency is determined by constraining the relative evolutionary stages of the components in a multiple system. Methods. Spectral energy distributions (SEDs) for known multiple protostars in Perseus were constructed from literature data. Herschel PACS photometric maps were used to sample the peak of the SED for systems with separations ≥7 , a crucial aspect in determining the evolutionary stage of a protostellar system. Inclination effects and the surrounding envelope and outflows were considered to decouple source geometry from evolution. This together with the shape and derived properties from the SED was used to determine each system's coevality as accurately as possible. SED models were used to examine the frequency of non-coevality that is due to geometry. Results. We find a non-coevality frequency of 33 ± 10% from the comparison of SED shapes of resolved multiple systems. Other source parameters suggest a somewhat lower frequency of non-coevality. The frequency of apparent non-coevality that is due to random inclination angle pairings of model SEDs is 17 ± 0.5%. Observations of the outflow of resolved multiple systems do not suggest significant misalignments within multiple systems. Effects of unresolved multiples on the SED shape are also investigated. Conclusions. We find that one-third of the multiple protostellar systems sampled here are non-coeval, which is more than expected from random geometric orientations. The other two-thirds are found to be coeval. Higher order multiples show a tendency to be non-coeval. The frequency of non-coevality found here is most likely due to formation and enhanced by dynamical evolution.

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Section: Outflowssupporting

confidence: 85%

Do siblings always form and evolve simultaneously? Testing the coevality of multiple protostellar systems through SEDs

Murillo

Dishoeck

Tobin

et al. 2016

A&A

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“…The maximum velocities of 2 km s −1 are also consistent with model predictions of FHSC outflow velocities (Price et al 2012). In comparison, Gerin et al (2015) detect outflows associated with the Barnard 1b FHSC candidate with velocities up to ∼7 km s −1 and estimated dynamical age of ∼1000 and ∼2000 years for B1b-S and B1b-N, respectively. They note that the outflow masses, mass-loss rate, and mechanical luminosities agree with theoretical predictions of FHSC.…”

Section: Outflows As Tracers Of Hydrostatic Coresmentioning

confidence: 90%

Detection of Irregular, Submillimeter Opaque Structures in the Orion Molecular Clouds: Protostars within 10,000 yr of Formation?

Karnath

Megeath

Tobin

et al. 2020

ApJ

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We report ALMA and VLA continuum observations that potentially identify the four youngest protostars in the Orion Molecular Clouds taken as part of the Orion VANDAM program. These are distinguished by bright, extended, irregular emission at 0.87 mm and 8 mm and are optically thick at 0.87 mm. These structures are distinct from the disk or point-like morphologies seen toward the other Orion protostars. The 0.87 mm emission implies temperatures of 41-170 K, requiring internal heating. The bright 8 mm emission implies masses of 0.5 to 1.2 M assuming standard dust opacity models. One source has a Class 0 companion, while another exhibits substructure indicating a companioncandidate. Three compact outflows are detected, two of which may be driven by companions, with dynamical times of ∼300 to ∼1400 years. The slowest outflow may be driven by a first hydrostatic core. These protostars appear to trace an early phase when the centers of collapsing fragments become optically thick to their own radiation and compression raises the gas temperature. This phase is thought to accompany the formation of hydrostatic cores. A key question is whether these structures are evolving on free fall times of ∼ 100 years, or whether they are evolving on Kelvin-Helmholtz times of several thousand years. The number of these sources imply a lifetime of ∼6000 years, in closer agreement with the Kelvin-Helmholtz time. In this case, rotational and/or magnetic support could be slowing the collapse.

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“…At a temperature of 2000 K, H 2 dissociates which consumes energy and eventually leads to a second, fast collapse until pressure again balances the gravitational force and the second core or Class 0 protostar forms, subsequently. Since the FHSC stage is expected to be short-lived (∼1000 yr for a strongly magnetized core, Commerçon et al 2012), its detection is rather challenging and until now, only one of the candidates, Barnard 1b-N (Gerin et al 2015), seems to fulfil the require-The reduced datacubes are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.ustrasbg.fr/viz-bin/qcat?J/A+A/ ments predicted by magneto-hydrodynamic (MHD) simulations. The results of such simulations depend on the level of rotation and the mass-to-magnetic-flux ratio but they generally show the FHSC to be the driving source of a poorly collimated, lowvelocity outflow (∼ 5 km/s) (e.g., Hennebelle & Fromang 2008;Machida et al 2008;Ciardi & Hennebelle 2010;Commerçon et al 2010;Tomida et al 2010;Machida 2014), unlike Class 0 protostars which after formation launch a highly collimated jet with velocities of >30 km/s (Banerjee & Pudritz 2006;Machida et al 2008;Machida 2014).…”

Section: Introductionmentioning

confidence: 99%

The dynamically young outflow of the Class 0 protostar Cha-MMS1

Busch

Беллоче

Cabrit

et al. 2020

A&A

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Context. On the basis of its low luminosity, its chemical composition, and the absence of a large-scale outflow, the dense core Cha-MMS1 located in the Chamaeleon I molecular cloud was proposed as a first hydrostatic core (FHSC) candidate a decade ago. Aims. Our goal is to test this hypothesis by searching for a slow, compact outflow driven by Cha-MMS1 that would match the predictions of MHD simulations for this short phase of star formation. Methods. We use the Atacama Large Millimetre/submillimetre Array (ALMA) to map Cha-MMS1 at high angular resolution in CO 3-2 and 13 CO 3-2 as well as in continuum emission. Results. We report the detection of a bipolar outflow emanating from the central core, along a (projected) direction roughly parallel to the filament in which Cha-MMS1 is embedded and perpendicular to the large-scale magnetic field. The morphology of the outflow indicates that its axis lies close to the plane of the sky. We measure velocities corrected for inclination of more than 90 km s −1 which is clearly incompatible with the expected properties of a FHSC outflow. Several properties of the outflow are determined and compared to previous studies of Class 0 and Class I protostars. The outflow of Cha-MMS1 has a much smaller momentum force than the outflows of other Class 0 protostars. In addition, we find a dynamical age of 200-3000 yr indicating that Cha-MMS1 might be one of the youngest ever observed Class 0 protostars. While the existence of the outflow suggests the presence of a disk, no disk is detected in continuum emission and we derive an upper limit of 55 au to its radius. Conclusions. We conclude that Cha-MMS1 has already gone through the FHSC phase and is a young Class 0 protostar, but it has not brought its outflow to full power yet.

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Nascent bipolar outflows associated with the first hydrostatic core candidates Barnard 1b-N and 1b-S

Cited by 56 publications

References 30 publications

Do siblings always form and evolve simultaneously? Testing the coevality of multiple protostellar systems through SEDs

Do siblings always form and evolve simultaneously? Testing the coevality of multiple protostellar systems through SEDs

Detection of Irregular, Submillimeter Opaque Structures in the Orion Molecular Clouds: Protostars within 10,000 yr of Formation?

The dynamically young outflow of the Class 0 protostar Cha-MMS1

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