On the Nature of the Deeply Embedded Protostar Omc-2 Fir 4

Furlan, Elise; Megeath, S. Thomas; Osorio, M. R. Zapatero; Stutz, Amelia M.; Fischer, William J.; Ali, B.; Stanke, T.; Manoj, P.; Adams, Joseph D.; Tobin, John J.

doi:10.1088/0004-637x/786/1/26

Cited by 27 publications

(76 citation statements)

References 57 publications

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“…Four cores coincide with HOPS protostars. The cores #20 and 25 coincide with the FIR 3 and 4 (see, e.g., Furlan et al 2014). FIR 5 does not appear as a dense core in the ALMA data, although, it is within ∼4 ′′ of the cores #28 and 29.…”

Section: Structure Of the Omc-2/3 At 1 000 Au Resolutionmentioning

confidence: 84%

“…Finally, we also use the catalog of Spitzer-identified protostars and stars with disks from the HOPS survey (Megeath et al 2012 for the disks and Furlan et al 2016 for the protostars). The protostars and stars with disks are shown in Fig.…”

Section: Observations and Methodsmentioning

confidence: 99%

“…communication). The other sources have flat to Class II SEDs between 1.6-24 µm; these may be protostars observed near a face-on inclination and/or with lower mass envelope (Furlan et al 2016).…”

Section: Identification Of Dense Coresmentioning

confidence: 99%

“…We cross-correlated the positions of the cores with the protostars (Furlan et al 2016) and stars with disks (Megeath et al 2012). The objects were considered coincident if their centroids were within a 2 ′′ radius of the protostars or disks.…”

Section: Identification Of Dense Coresmentioning

confidence: 99%

“…The ISF, located in the northern part of Orion A, is an ∼8 pc long structure with the line-mass of 385 × (d/pc) 3/8 M ⊙ pc −1 from 0.05 pc ¡ d ¡ 8.5 pc of projected separation from the filament ridge (Stutz & Gould 2016). Importantly, the young stellar population of Orion A is well characterised with Spitzer (Megeath et al 2012) and Herschel (the Herschel Orion Protostar Survey, HOPS; Furlan et al 2016). Combined, these properties make the ISF an outstanding, and currently unique, region in which to study the physics of how highly super-critical filamentary gas fragments into (high-and low-mass) protostars.…”

Section: Introductionmentioning

confidence: 99%

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Resolving the fragmentation of high line-mass filaments with ALMA: the integral shaped filament in Orion A

Kainulainen

Stutz

Stanke³

et al. 2017

A&A

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We study the fragmentation of the nearest high line-mass filament, the integral shaped filament (ISF, line-mass ∼ 400 M ⊙ pc −1 ) in the Orion A molecular cloud. We have observed a 1.6 pc long section of the ISF with the Atacama Large Millimetre/submillimeter Array (ALMA) at 3 mm continuum emission, at a resolution of ∼3 ′′ (1 200 AU). We identify from the region 43 dense cores with masses about a solar mass. 60% of the ALMA cores are protostellar and 40% are starless. The nearest neighbour separations of the cores do not show a preferred fragmentation scale; the frequency of short separations increases down to 1 200 AU. We apply a twopoint correlation analysis on the dense core separations and show that the ALMA cores are significantly grouped at separations below ∼17 000 AU and strongly grouped below ∼6 000 AU. The protostellar and starless cores are grouped differently: only the starless cores group strongly below ∼6 000 AU. In addition, the spatial distribution of the cores indicates periodic grouping of the cores into groups of ∼30 000 AU in size, separated by ∼50 000 AU. The groups coincide with dust column density peaks detected by Herschel. These results show hierarchical, two-mode fragmentation in which the maternal filament periodically fragments into groups of dense cores. Critically, our results indicate that the fragmentation models for lower line-mass filaments (∼ 16 M ⊙ pc −1 ) fail to capture the observed properties of the ISF. We also find that the protostars identified with Spitzer and Herschel in the ISF are grouped at separations below ∼17 000 AU. In contrast, young stars with disks do not show significant grouping. This suggests that the grouping of dense cores is partially retained over the protostar lifetime, but not over the lifetime of stars with disks. This is in agreement with a scenario where protostars are ejected from the maternal filament by the slingshot mechanism, a model recently proposed for the ISF by Stutz & Gould. The separation distributions of the dense cores and protostars may also provide an evolutionary tracer of filament fragmentation.

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Section: Structure Of the Omc-2/3 At 1 000 Au Resolutionmentioning

confidence: 84%

Section: Observations and Methodsmentioning

confidence: 99%

Section: Identification Of Dense Coresmentioning

confidence: 99%

Section: Identification Of Dense Coresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Resolving the fragmentation of high line-mass filaments with ALMA: the integral shaped filament in Orion A

Kainulainen

Stutz

Stanke³

et al. 2017

A&A

Self Cite

112

151

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Depletion of chlorine into HCl ice in a protostellar core

Kama

Caux

López-Sepulcre

et al. 2015

A&A

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Context. The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances < 10 −5 has not yet been well studied. Aims. Our aim here is to study the depletion of chlorine in the protostellar core, OMC-2 FIR 4. Methods. We observed transitions of HCl and H 2 Cl + towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H 2 hyperfine collisional excitation rate coefficients. Results. A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9 × 10 −11 , a factor of only 10 −3 that of volatile elemental chlorine. The H 2 Cl + lines are detected in absorption and trace a tenuous foreground cloud, where we find no depletion of volatile chlorine. Conclusions. Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form. Gas-phase HCl is a minor, but diagnostically key reservoir, with an abundance of 10 −10 in most of the protostellar core. We find the [ 35 Cl]/[ 37 Cl] ratio in OMC-2 FIR 4 to be 3.2 ± 0.1, consistent with the solar system value.

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Herschel/PACS far-IR spectral imaging of a jet from an intermediate mass protostar in the OMC-2 region

González-García

Manoj

Watson

et al. 2016

A&A

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We present the first detection of a jet in the far-IR [O I] lines from an intermediate mass protostar. We have carried out a Herschel/PACS spectral mapping study in the [O I] lines of OMC-2 FIR 3 and FIR 4, two of the most luminous protostars in Orion outside of the Orion Nebula. The spatial morphology of the fine structure line emission reveals the presence of an extended photodissociation region (PDR) and a narrow, but intense jet connecting the two protostars. The jet seen in [O I] emission is spatially aligned with the Spitzer/IRAC 4.5 µm jet and the CO (6-5) molecular outflow centered on FIR 3. The mass loss rate derived from the total [O I] 63 µm line luminosity of the jet is 7.7 ×10 −6 M yr −1 , more than an order of magnitude higher than that measured for typical low mass class 0 protostars. The implied accretion luminosity is significantly higher than the observed bolometric luminosity of FIR 4, indicating that the [O I] jet is unlikely to be associated with FIR 4. We argue that the peak line emission seen toward FIR 4 originates in the terminal shock produced by the jet driven by FIR 3. The higher mass-loss rate that we find for FIR 3 is consistent with the idea that intermediate mass protostars drive more powerful jets than their low-mass counterparts. Our results also call into question the nature of FIR 4.

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On the Nature of the Deeply Embedded Protostar Omc-2 Fir 4

Cited by 27 publications

References 57 publications

Resolving the fragmentation of high line-mass filaments with ALMA: the integral shaped filament in Orion A

Resolving the fragmentation of high line-mass filaments with ALMA: the integral shaped filament in Orion A

Depletion of chlorine into HCl ice in a protostellar core

Herschel/PACS far-IR spectral imaging of a jet from an intermediate mass protostar in the OMC-2 region

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