CHARACTERIZING THE YOUNGEST<i>HERSCHEL</i>-DETECTED PROTOSTARS. I. ENVELOPE STRUCTURE REVEALED BY CARMA DUST CONTINUUM OBSERVATIONS

Tobin, John J.; Stutz, Amelia M.; Megeath, S. Thomas; Fischer, William J.; Henning, Thomas; Ragan, S. E.; Ali, B.; Stanke, T.; Manoj, P.; Calvet, Nuria; Hartmann, L.

doi:10.1088/0004-637x/798/2/128

Cited by 48 publications

(77 citation statements)

References 57 publications

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“…MMS10 (no ALMA cores): The appearance is similar to that evidenced by the Chini et al (1997) data, with one local maximum in an elongated clump. FIR 1a,b,c (cores #8,[10][11][12][13][14]: The ALMA data resolves FIR 1a into four dense cores (three of them have previously been detected from arcsecond-resolution continuum emission data by Tobin et al 2015). One of the peaks (core #11) is close (3.…”

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

confidence: 99%

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

112

151

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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: 99%

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

112

151

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“…Herschel/ PACS spectra for eightPBRs were later obtained by the HOPS team as part of the Herschel open time (OT) program (Tobin et al 2016). The DIGIT program surveyed 94 young stellar objects in different evolutionary stages with Herschel and obtained far-IR spectra of 24 Herbig Ae/Be stars, 40 T Tauri stars,and 30 protostars in nearby (d  400 pc) star-forming regions (van Kempen et al 2010;Cieza et al 2013;Dionatos et al 2013;Fedele et al 2013;Green et al 2013bGreen et al , 2013aGreen et al , 2016Meeus et al 2013;Sturm et al 2013;Lee et al 2014bLee et al , 2014a. The Herschel/PACS spectra of 30 protostars in the DIGIT sample were presented in Green et al (2013b).…”

Section: The Samplementioning

confidence: 99%

The Evolution of Far-Infrared Co Emission From Protostars

Manoj

Green

Megeath

et al. 2016

ApJ

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We investigate the evolution of far-IR CO emission from protostars observed with Herschel/PACS for 50 sources from the combined sample of HOPS and DIGIT Herschel key programs. From the uniformly sampled spectral energy distributions, whose peaks are well sampled, we computed the L bol , T bol ,and L L bol smm for these sources to search for correlations between far-IR CO emission and protostellar properties. We find a strong and tight correlation between far-IR CO luminosity (L CO fir ) and the bolometric luminosity (L bol ) of the protostars with µ L L CO fir bol 0.7 . We, however, do not find a strong correlation between L CO fir and protostellar evolutionary indicators, T bol and L L bol smm . FIRCO emission from protostars traces the currently shocked gas by jets/outflows, and far-IR CO luminosity, L CO fir , is proportional to the instantaneous mass-loss rate,Ṁ out . The correlation between L CO fir and L bol , then, is indicative of instantaneousṀ out tracking instantaneousṀ acc . The lack of acorrelation between L CO fir and evolutionary indicators T bol and L L bol smm suggests thatṀ out and, therefore,Ṁ acc do not show any clear evolutionary trend. These results are consistent with mass accretion/ejection in protostars being episodic. Taken together with the previous finding that the time-averaged mass-ejection/accretion rate declines during the protostellar phase, our results suggest that the instantaneous accretion/ejection rate of protostars is highly time variable and episodic, but the amplitude and/or frequency of this variability decreases with time such that the timeaveraged accretion/ejection rate declines with system age.

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“…1 In the present work, we have adopted a distance of d = 420 pc to the source to be consistent with the most recent studies of SMM3 (Stutz et al 2013;Tobin et al 2015;Furlan et al 2016). We note that in Papers I-III, we assumed a distance of 450 pc, which is a factor of 1.07 larger than used here.…”

Section: Introductionmentioning

confidence: 66%

“…′′ 56), SMM3 was found to be the second brightest source among the 14 target sources. The total (gas+dust) mass derived for SMM3 by Tobin et al (2015), M = 7.0 ± 0.7 M ⊙ , is much higher than that derived earlier by S13 using a MBB fitting technique, which underpredicted the 870 µm flux density of the source (see Tobin et al 2015 and Sect. 4.1 herein for further discussion and different assumptions used).…”

Section: Introductionmentioning

confidence: 79%

“…The derived SED properties led S13 to the conclusion that SMM3 is likely a Class 0 object, which supports our earlier suggestion (Papers I and III). Tobin et al (2015) included SMM3 in their Combined Array for Research for Millimetre Astronomy (CARMA) 2.9 mm continuum imaging survey of Class 0 objects in Orion. This was the first high angular resolution study of SMM3.…”

Section: Introductionmentioning

confidence: 99%

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Characterising the physical and chemical properties of a young Class 0 protostellar core embedded in the Orion B9 filament

Miettinen

2016

Astrophys Space Sci

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Deeply embedded low-mass protostars can be used as testbeds to study the early formation stages of solar-type stars, and the prevailing chemistry before the formation of a planetary system. The present study aims to characterise further the physical and chemical properties of the protostellar core Orion B9-SMM3. The Atacama Pathfinder EXperiment (APEX) telescope was used to perform a follow-up molecular line survey of SMM3. The observations were done using the single pointing (frequency range 218.2-222.2 GHz) and on-the-fly mapping methods (215.1-219.1 GHz). These new data were used in conjunction with our previous data taken by the APEX and Effelsberg 100 m telescopes. The following species were identified from the frequency range 218.2-222.2 GHz:13 CO, C 18 O, SO, para-H 2 CO, and E 1 -type CH 3 OH. The mapping observations revealed that SMM3 is associated with a dense gas core as traced by DCO + and p-H 2 CO. Altogether three different p-H 2 CO transitions were detected with clearly broadened linewidths (∆v ∼ 8.2 − 11 km s −1 in FWHM). The derived p-H 2 CO rotational temperature, 64 ± 15 K, indicates the presence of warm gas. We also detected a narrow p-H 2 CO line (∆v = 0.42 km s −1 ) at the systemic velocity. The p-H 2 CO abundance for the broad component appears to be enhanced by two orders of magnitude with respect to the narrow line value (∼ 3×10 −9 versus ∼ 2×10 −11 ). The detected methanol line shows a linewidth similar to those of the broad p-H 2 CO lines, which indicates their coexistence. The CO isotopologue data suggest that the CO depletion factor decreases from ∼ 27 ± 2 towards the core centre to a value of ∼ 8 ± 1 towards the core edge. In the latter position, the N 2 D + /N 2 H + ratio is revised down to 0.14 ± 0.06. The origin of the subfragments inside the SMM3 core we found previously can be understood in terms of the Jeans instability if non-thermal motions are taken into account. The estimated fragmentation timescale, and the derived chemical abundances suggest that SMM3 is a few times 10 5 yr old, in good agreement with its Class 0 classification inferred from the spectral energy distribution analysis. The broad p-H 2 CO and CH 3 OH lines, and the associated warm gas provide the first clear evidence of a molecular outflow driven by SMM3.

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CHARACTERIZING THE YOUNGESTHERSCHEL-DETECTED PROTOSTARS. I. ENVELOPE STRUCTURE REVEALED BY CARMA DUST CONTINUUM OBSERVATIONS

Cited by 48 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

The Evolution of Far-Infrared Co Emission From Protostars

Characterising the physical and chemical properties of a young Class 0 protostellar core embedded in the Orion B9 filament

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