NGC 1333—Protostars, Dust Shells, and Triggered Star Formation

Sandell, G.; Knee, L. B. G.

doi:10.1086/318060

Cited by 139 publications

(191 citation statements)

References 28 publications

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“…NGC 1333-IRAS2A was first identified in 450 μm and 850 μm continuum observations (Sandell et al 1994;Sandell & Knee 2001), and is also detected at cm-wavelengths Reipurth et al 2002) and as a compact 3 mm continuum source (Jørgensen et al 2004). CO maps of the IRAS2 region show two outflows, directed north-south and east-west (Liseau et al 1988;Knee & Sandell 2000), both originating near IRAS2A.…”

Section: Ngc 1333-iras2amentioning

confidence: 99%

Toward understanding the formation of multiple systems

Maury¹,

André²,

Hennebelle

et al. 2010

A&A

157

230

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Context. The formation process of binary stars and multiple systems is poorly understood. The multiplicity rate of Class II premain-sequence stars and Class I protostars is well documented and known to be high (∼ 30% to 50% between ∼100 and 4000 AU). However, optical / near-infrared observations of Class I/Class II YSOs barely constrain the pristine properties of multiple systems, since dynamical evolution can quickly alter these properties during the protostellar phase. Aims. Here, we seek to determine the typical outcome of protostellar collapse and to constrain models of binary formation by core fragmentation during collapse, using high-resolution millimeter continuum imaging of very young (Class 0) protostars observed at the beginning of the main accretion phase. Methods. We carried out a pilot high-resolution study of 5 Class 0 objects, including 3 Taurus sources and 2 Perseus sources, using the most extended (A) configuration of the IRAM Plateau de Bure Interferometer (PdBI) at 1.3 mm. Our PdBI observations have a typical HPBW resolution ∼0.3 −0.5 and rms continuum sensitivity ∼0.1−1 mJy/beam, which allow us to probe the multiplicity of Class 0 protostars down to separations a ∼ 50 AU and circumstellar mass ratios q ∼ 0.07. Results. We detected all 5 primary Class 0 sources in the 1.3 mm dust continuum. A single component associated with the primary Class 0 object was detected in the case of the three Taurus sources, while robust evidence of secondary components was found toward the two Perseus sources: L1448-C and NGC1333-IR2A. We show that the secondary 1.3 mm continuum component detected ∼600 AU south-east of L1448-C, at a position angle close to that of the CO(2−1) jet axis traced by our data, is an outflow feature directly associated with the powerful jet driven by L1448-C. The secondary 1.3 mm continuum component detected ∼1900 AU southeast of NGC1333-IR2A may either be a genuine protostellar companion or trace the edge of an outflow cavity. Therefore, our PdBI observations revealed only wide (>1500 AU) protobinary systems and/or outflow-generated features. Conclusions. When combined with previous millimeter interferometric observations of Class 0 protostars, our pilot PdBI study tentatively suggests that the binary fraction in the ∼75−1000 AU range increases from the Class 0 to the Class I stage. It also seems to argue against purely hydrodynamic models of binary star formation. We briefly discuss possible alternative scenarios to reconcile the low multiplicity rate of Class 0 protostars on small scales with the higher binary fraction observed at later (e.g. Class I) evolutionary stages.

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Section: Ngc 1333-iras2amentioning

confidence: 99%

Toward understanding the formation of multiple systems

Maury¹,

André²,

Hennebelle

et al. 2010

A&A

157

230

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“…The above studies show a common spectral index of the clump mass distribution of ∼2.3. There are only a few exceptions: the studies of Sandell et al (2001) and Coppin et al (2000) show indices of ∼1.5.…”

Section: Clump Mass Distributionmentioning

confidence: 99%

The Giant Molecular Cloud associated with RCW 106

Mookerjea¹,

Krämer²,

Nielbock

et al. 2004

A&A

151

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Abstract.We have mapped the dust continuum emission from the molecular cloud covering a region of 28 pc × 94 pc associated with the well-known H  region RCW 106 at 1.2 mm using SIMBA on SEST. The observations, having an HPBW of 24 (0.4 pc), reveal 95 clumps, of which about 50% have MSX associations and only 20% have IRAS associations. Owing to their higher sensitivity to colder dust and higher angular resolution the present observations identify new emission features and also show that most of the IRAS sources in this region consist of multiple dust emission peaks. The detected millimeter sources (MMS) include on one end the exotic MMS5 (associated with IRAS 16183-4958, one of the brightest infrared sources in our Galaxy) and the bright (and presumably cold) source MMS54, with no IRAS or MSX associations on the other end. Around 10% of the sources are associated with signposts of high mass star formation activity. Assuming a uniform dust temperature of 20 K we estimate the total mass of the GMC associated with RCW 106 to be ∼10 5 M . The constituent millimeter clumps cover a range of masses and radii between 40 to 10 4 M and 0.3 to 1.9 pc. Densities of the clumps range between (0.5-6) ×10 4 cm −3 . We have decomposed the continuum emission into Gaussian and arbitrary shaped clumps using the two independent structure analysis tools gaussclumps and clumpfind respectively. The clump mass spectrum was found to have an index α of 1.6 ± 0.3, independent of the decomposition algorithm used. The index of the mass spectrum for the mass and length scales covered here are consistent with results derived from large scale CO observations.

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“…They have attracted significant attention owing to their strong continuum emission, powerful outflows, and rich chemistry (André & Montmerle 1994;Blake et al 1995;Bottinelli et al 2007). They were first identified as water maser spots by Ho & Barrett (1980) and later confirmed as protostellar candidates by IRAS observations (Jennings et al 1987) and resolved individually in JCMT-SCUBA submm continuum maps (Sandell et al 1991;Sandell & Knee 2001;Di Francesco et al 2008). Using mm interferometry, it was subsequently found that both protostars are in proto-multiple systems (Lay et al 1995;Looney et al 2000).…”

Section: Introductionmentioning

confidence: 99%

APEX-CHAMP⁺high-JCO observations of low-mass young stellar objects

Yıldız

Kristensen

Dishoeck

et al. 2012

A&A

110

243

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Context. The NGC 1333 IRAS 4A and IRAS 4B sources are among the most well-studied Stage 0 low-mass protostars, which drive prominent bipolar outflows. Spectrally resolved molecular emission lines provide crucial information about the physical and chemical structure of the circumstellar material as well as the dynamics of the different components. Most studies have so far concentrated on the colder parts (T ≤ 30 K) of these regions. Aims. The aim is to characterize the warmer parts of the protostellar envelope using the new generation of submillimeter instruments. This will allow us to quantify the feedback of the protostars on their surroundings in terms of shocks, ultraviolet (UV) heating, photodissociation, and outflow dispersal. Methods. The dual frequency 2 × 7 pixel 650/850 GHz array receiver CHAMP + mounted on APEX was used to obtain a fully sampled, large-scale ∼4 × 4 map at 9 resolution of the IRAS 4A/4B region in the 12 CO J = 6-5 line. Smaller maps were observed in the 13 CO 6-5 and [C i] J = 2-1 lines. In addition, a fully sampled 12 CO J = 3-2 map made with HARP-B on the JCMT is presented and deep isotopolog observations are obtained at selected outflow positions to constrain the optical depth. Complementary Herschel-HIFI and ground-based lines of CO and its isotopologs, from J = 1-0 up to 10-9 (E u /k ≈ 300 K), are collected at the source positions and used to construct velocity-resolved CO ladders and rotational diagrams. Radiative-transfer models of the dust and lines are used to determine the temperatures and masses of the outflowing and photon-heated gas and infer the CO abundance structure. Results. Broad CO emission-line profiles trace entrained shocked gas along the outflow walls, which have an average temperature of ∼100 K. At other positions surrounding the outflow and the protostar, the 6-5 line profiles are narrow indicating UV excitation. The narrow 13 CO 6-5 data directly reveal the UV heated gas distribution for the first time. The amount of UV-photon-heated gas and outflowing gas are quantified from the combined 12 CO and 13 CO 6-5 maps and found to be comparable within a 20 radius around IRAS 4A, which implies that UV photons can affect the gas as much as the outflows. Weak [C I] emission throughout the region indicates that there is a lack of CO dissociating photons. Our modeling of the C 18 O lines demonstrates the necessity of a "drop" abundance profile throughout the envelopes where the CO freezes out and is reloaded back into the gas phase through grain heating, thus providing quantitative evidence of the CO ice evaporation zone around the protostars. The inner abundances are less than the canonical value of CO/H 2 = 2.7 × 10 −4 , however, implying that there is some processing of CO into other species on the grains. The implications of our results for the analysis of spectrally unresolved Herschel data are discussed.

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NGC 1333—Protostars, Dust Shells, and Triggered Star Formation

Cited by 139 publications

References 28 publications

Toward understanding the formation of multiple systems

Toward understanding the formation of multiple systems

The Giant Molecular Cloud associated with RCW 106

APEX-CHAMP⁺high-JCO observations of low-mass young stellar objects

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NGC 1333—Protostars, Dust Shells, and Triggered Star Formation

Cited by 139 publications

References 28 publications

Toward understanding the formation of multiple systems

Toward understanding the formation of multiple systems

The Giant Molecular Cloud associated with RCW 106

APEX-CHAMP+high-JCO observations of low-mass young stellar objects

Contact Info

Product

Resources

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APEX-CHAMP⁺high-JCO observations of low-mass young stellar objects