First Science Observations With Sofia/Forcast: Properties of Intermediate-Luminosity Protostars and Circumstellar Disks in Omc-2

Adams, Joseph D.; Herter, T.; Osorio, M. R. Zapatero; Macías, Enrique; Megeath, S. Thomas; Fischer, William J.; Ali, B.; Calvet, Nuria; D’Alessio, Paola; Buizer, James M. De; Gull, G. E.; Henderson, Christine; Keller, L. D.; Morris, Mark; Remming, Ian S.; Schoenwald, Justin; Shuping, R. Y.; Stacey, G. J.; Stanke, T.; Stutz, Amelia M.; Vacca, William D.

doi:10.1088/2041-8205/749/2/l24

Cited by 30 publications

(70 citation statements)

References 31 publications

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“…While earlier studies attributed a luminosity of 400 or 1000 L to OMC-2 FIR 4 (Mezger et al 1990;Crimier et al 2009), recent Herschel and SOFIA observations found 30 to 50 L (Adams et al 2012). Adams et al (2012) further found an envelope mass of 10 M for FIR 4, while previous authors found it to be ∼30 M (Mezger et al 1990;Crimier et al 2009) and continuum interferometry has yielded even larger estimates, 60 M (Shimajiri et al 2008).…”

Section: Introductionmentioning

confidence: 88%

TheHerschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS)

Kama

López-Sepulcre

Dominik

et al. 2013

A&A

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Context. Broadband spectral surveys of protostars offer a rich view of the physical, chemical and dynamical structure and evolution of star-forming regions. The Herschel Space Observatory opened up the terahertz regime to such surveys, giving access to the fundamental transitions of many hydrides and to the high-energy transitions of many other species. Aims. A comparative analysis of the chemical inventories and physical processes and properties of protostars of various masses and evolutionary states is the goal of the Herschel CHEmical Surveys of Star forming regions (CHESS) key program. This paper focusses on the intermediate-mass protostar, OMC-2 FIR 4. Methods. We obtained a spectrum of OMC-2 FIR 4 in the 480 to 1902 GHz range with the HIFI spectrometer onboard Herschel and carried out the reduction, line identification, and a broad analysis of the line profile components, excitation, and cooling. Results. We detect 719 spectral lines from 40 species and isotopologs. The line flux is dominated by CO, H 2 O, and CH 3 OH. The line profiles are complex and vary with species and upper level energy, but clearly contain signatures from quiescent gas, a broad component likely due to an outflow, and a foreground cloud. Conclusions. We find abundant evidence for warm, dense gas, as well as for an outflow in the field of view. Line flux represents 2% of the 7 L luminosity detected with HIFI in the 480 to 1250 GHz range. Of the total line flux, 60% is from CO, 13% from H 2 O and 9% from CH 3 OH. A comparison with similar HIFI spectra of other sources is set to provide much new insight into star formation regions, a case in point being a difference of two orders of magnitude in the relative contribution of sulphur oxides to the line cooling of Orion KL and OMC-2 FIR 4.

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Section: Introductionmentioning

confidence: 88%

TheHerschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS)

Kama

López-Sepulcre

Dominik

et al. 2013

A&A

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“…Midinfrared imaging at ∼4 ′′ resolution resolves eight sources in the region (Adams et al 2012) and mm-wavelength data detect 12 fragments altogether (Shimajiri et al 2008). The ALMA data shows how the region is inter-connected by a filamentary structure from which we identify 13 dense cores.…”

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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“…The L bol and T bol values of HOPS and PBR sources listed in Table 1 agree well with those presented in Furlan et al (2016): for most sources they agree within 5%-6%. The major difference is for HOPS 369, which has been modeled as a double source comprising a diskdominated source and a protostar by Adams et al (2012). We integrated the SED upward of 37 μm to account only for the protostellar component (see Manoj et al 2013), whereas Furlan et al (2016) integrated under the entire SED to obtain L bol and T bol .…”

Section: Protostellar Propertiesmentioning

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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First Science Observations With Sofia/Forcast: Properties of Intermediate-Luminosity Protostars and Circumstellar Disks in Omc-2

Cited by 30 publications

References 31 publications

TheHerschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS)

TheHerschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS)

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

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