The Evolution of Outflow‐Envelope Interactions in Low‐Mass Protostars

Arce, Héctor G.; Sargent, Anneila I.

doi:10.1086/505104

Cited by 282 publications

(457 citation statements)

References 82 publications

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“…The position angle of the whole outflow (redshifted and blueshifted lobes) can be determined with great accuracy, 108N4 AE 0N1, and its collimation angle is $13 . This small collimation angle is consistent with an extremely young source (Arce & Sargent 2006). With our present angular resolution (2B8 ; 1B7), we can resolve the redshifted lobe, while the blueshifted lobe was only resolved in the eastYwest orientation (the major axis).…”

Section: -356 Bipolar Outflow: the Most Powerfulsupporting

confidence: 80%

Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC 1 South Region

Zapata

Rodrı́guez

et al. 2006

ApJ

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We present high angular resolution (2B8 ; 1B7) SiO J ¼ 5 ! 4, v ¼ 0 line observations of the OMC 1S region in the Orion Nebula made using the Submillimeter Array (SMA). We detect for the first time a cluster of four compact bipolar and monopolar outflows that show high-, moderate-, and low-velocity gas and appear to be energized by millimeter and infrared sources associated with this region. The SiO molecular outflows are compact (<3500 AU ), and in most of the cases, they are located very close to their exciting sources. We thus propose that the SiO thermal emission is tracing the youngest and most highly excited parts of the outflows that cannot be detected by other molecules. Moreover, since the ambient cloud is weak in the SiO line emission, these observations can reveal flows that in other molecular transitions will be confused with the ambient velocity cloud emission.

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Section: -356 Bipolar Outflow: the Most Powerfulsupporting

confidence: 80%

Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC 1 South Region

Zapata

Rodrı́guez

et al. 2006

ApJ

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“…This quantity has been used to distinguish Stage 0 objects from the more evolved Stage I objects, in which the outflow angle has been widened (Bachiller & Tafalla 1999;Arce & Sargent 2006). The R coll for IRAS 4A is found to be 5.3 ± 0.5 for the blue outflow lobe and 7.5 ± 0.5 for the red outflow lobe.…”

Section: Morphologymentioning

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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“…These outflows emanating from protostars collide with the remaining molecular cloud and disperse the surrounding material, and determine the evolution of the dense core where the star is born (Arce & Sargent 2006). In this sense, the study of these mass-loss processes and the molecular environment of the embedded objects from which they emanate has became an important tool in order to better understand the earliest stages of stellar evolution.…”

Section: Introductionmentioning

confidence: 99%

Dense gas and the nature of the outflows

Sepúlveda

Anglada

Estalella

et al. 2011

A&A

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We present the results of the observations of the (J, K) = (1, 1) and the (J, K) = (2, 2) inversion transitions of the NH 3 molecule toward a large sample of 40 regions with molecular or optical outflows, using the 37 m radio telescope of the Haystack Observatory. We detected NH 3 emission in 27 of the observed regions, which we mapped in 25 of them. Additionally, we searched for the 6 16 −5 23 H 2 O maser line toward six regions, detecting H 2 O maser emission in two of them, HH265 and AFGL 5173. We estimate the physical parameters of the regions mapped in NH 3 and analyze for each particular region the distribution of high density gas and its relationship with the presence of young stellar objects. In particular, we identify the deflecting high-density clump of the HH270/110 jet. We were able to separate the NH 3 emission from the L1641-S3 region into two overlapping clouds, one with signs of strong perturbation, probably associated with the driving source of the CO outflow, and a second, unperturbed clump, which is probably not associated with star formation. We systematically found that the position of the best candidate for the exciting source of the molecular outflow in each region is very close to an NH 3 emission peak. From the global analysis of our data we find that in general the highest values of the line width are obtained for the regions with the highest values of mass and kinetic temperature. We also found a correlation between the nonthermal line width and the bolometric luminosity of the sources, and between the mass of the core and the bolometric luminosity. We confirm with a larger sample of regions the conclusion of Anglada et al. (1997) that the NH 3 line emission is more intense toward molecular outflow sources than toward sources with optical outflow, suggesting a possible evolutionary scheme in which young stellar objects associated with molecular outflows progressively lose their neighboring high-density gas, weakening both the NH 3 emission and the molecular outflow in the process, and making optical jets more easily detectable as the total amount of gas decreases.

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The Evolution of Outflow‐Envelope Interactions in Low‐Mass Protostars

Cited by 282 publications

References 82 publications

Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC 1 South Region

Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC 1 South Region

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

Dense gas and the nature of the outflows

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The Evolution of Outflow‐Envelope Interactions in Low‐Mass Protostars

Cited by 282 publications

References 82 publications

Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC 1 South Region

Silicon Monoxide Observations Reveal a Cluster of Hidden Compact Outflows in the OMC 1 South Region

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

Dense gas and the nature of the outflows

Contact Info

Product

Resources

About

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