Hunting for hot corinos and WCCC sources in the OMC-2/3 filament

Bouvier, Mathilde; López-Sepulcre, A.; Ceccarelli, C.; Kahane, C.; Imai, Muneaki; Sakai, Nami; Yamamoto, Satoshi; Dagdigian, Paul J.

doi:10.1051/0004-6361/201937164

Cited by 29 publications

(30 citation statements)

References 74 publications

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“…location of sources within the clouds and the ratio of CH 3 OH/C 2 H indicating the environmental effect on the chemistry. However, single-dish observations of CH 3 OH are contaminated by the contribution of the photodissociation region of the molecular clouds hosting the protostar (Bouvier et al 2020). In addition, chemical surveys with single-dish telescopes are often less sensitive to detect the COMs in the vicinity of the protostars.…”

Section: Notesmentioning

confidence: 99%

“…Single-dish surveys showed no correlation between COMs and long carbon-chain molecules (Graninger et al 2016;Higuchi et al 2018). Interestingly, carbon-chain molecules tend to distribute at a larger spatial scale than that of COMs (Imai et al 2016;Oya et al 2017;Bouvier et al 2020). Aikawa et al (2020) demonstrated that the conditions of prestellar cores can result in a larger spatial extent of carbon-chain molecules that coexist with COMs or deficient of carbon-chain molecules in COM-rich sources.…”

Section: Introductionmentioning

confidence: 99%

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The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars

Yang

Sakai

Zhang

et al. 2021

ApJ

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To date, about two dozen low-mass embedded protostars exhibit rich spectra with lines of complex organic molecules (COMs). These protostars seem to possess a different enrichment in COMs. However, the statistics of COM abundance in low-mass protostars are limited by the scarcity of observations. This study introduces the Perseus ALMA Chemistry Survey (PEACHES), which aims at unbiasedly characterizing the chemistry of COMs toward the embedded (Class 0/I) protostars in the Perseus molecular cloud. Of the 50 embedded protostars surveyed, 58% of them have emission from COMs. 56%, 32%, and 40% of the protostars have CH 3 OH, CH 3 OCHO, and N-bearing COMs, respectively. The detectability of COMs depends neither on the averaged continuum brightness temperature, a proxy of the H 2 column density, nor on the bolometric luminosity and the bolometric temperature. For the protostars with detected COMs, CH 3 OH has a tight correlation with CH 3 CN, spanning more than two orders of magnitude in column densities normalized by the continuum brightness temperature, suggesting a chemical relation between CH 3 OH and CH 3 CN and a large chemical diversity in the PEACHES samples at the same time. A similar trend with more scatter is also found between all identified COMs, which hints at a common chemistry for the sources with COMs. The correlation between COMs is insensitive to the protostellar properties, such as the bolometric luminosity and the bolometric temperature. The abundance of larger COMs (CH 3 OCHO and CH 3 OCH 3 ) relative to that of smaller COMs (CH 3 OH and CH 3 CN) increases with the inferred gas column density, hinting at an efficient production of complex species in denser envelopes.

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Section: Notesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars

Yang

Sakai

Zhang

et al. 2021

ApJ

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“…Two related questions arise: (1) Why are hot corinos so difficult to find? While it is known that not all Class 0/I sources possess hot corinos (e.g., Sakai & Yamamoto 2013;Higuchi et al 2018;Bouvier et al 2020), observational biases might hamper their detection. (2) Why do coeval objects seem drastically different in their chemical composition?…”

Section: Introductionmentioning

confidence: 99%

Hot Corinos Chemical Diversity: Myth or Reality?

Simone

Ceccarelli

Codella

et al. 2020

ApJL

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After almost 20 years of hunting, only about a dozen hot corinos, hot regions enriched in interstellar complex organic molecules (iCOMs), are known. Of them, many are binary systems with the two components showing drastically different molecular spectra. Two obvious questions arise. Why are hot corinos so difficult to find and why do their binary components seem chemically different? The answer to both questions could be a high dust opacity that would hide the molecular lines. To test this hypothesis, we observed methanol lines at centimeter wavelengths, where dust opacity is negligible, using the Very Large Array interferometer. We targeted the NGC 1333 IRAS 4A binary system, for which one of the two components, 4A1, has a spectrum deprived of iCOMs lines when observed at millimeter wavelengths, while the other component, 4A2, is very rich in iCOMs. We found that centimeter methanol lines are similarly bright toward 4A1 and 4A2. Their non-LTE analysis indicates gas density and temperature (2 10 6 cm −3 and 100-190 K), methanol column density (∼10 19 cm −2), and extent (∼35 au in radius) similar in 4A1 and 4A2, proving that both are hot corinos. Furthermore, the comparison with previous methanol line millimeter observations allows us to estimate the optical depth of the dust in front of 4A1 and 4A2, respectively. The obtained values explain the absence of iCOMs line emission toward 4A1 at millimeter wavelengths and indicate that the abundances toward 4A2 are underestimated by ∼30%. Therefore, centimeter observations are crucial for the correct study of hot corinos, their census, and their molecular abundances.

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“…The Orion ALMA New Generation Survey (ORANGES) is a project aiming to study the molecular content, on small scales (≤1000 au), of the solar-type protostars located in the OMC-2/3 filament. It follows a large-scale (≤10 4 au) study of these same protostellar cores (Bouvier et al 2020). The focus of this previous study, carried out with the single-dish telescopes IRAM-30m 1 and Nobeyama-45m 2 , was to identify Warm Carbon Chain Chemistry (WCCC) protostars and hot corino candidates using observations of two species, CCH and CH 3 OH.…”

Section: Description Of the Projectmentioning

confidence: 99%

“…The ORANGES project consists of new ALMA observations at 246.2 GHz towards the same sample of sources studied in Bouvier et al (2020). The spatial resolution is about 0.…”

Section: Description Of the Projectmentioning

confidence: 99%

ORion Alma New GEneration Survey (ORANGES)

Bouvier

López-Sepulcre

Ceccarelli

et al. 2021

A&A

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Context. The spectral energy distribution (SED) in the millimetre to centimetre range is an extremely useful tool for characterising the dust in protostellar envelopes as well as free-free emission from the protostar and outflow. Actually, the evolutionary status of solar-type protostars is often based on their SED in the near-infrared to millimetre range. In addition, the presence or absence of free-free emission can be considered an indicator of the source evolutionary stage (Class 0/I versus Class II/III). While many studies have been carried out towards low- and high-mass protostars, little exists so far about solar-type protostars in high-mass star-forming regions, which are likely to be representatives of the conditions where the Solar System was born. Aims. In this work, we focus on the embedded solar-type protostars in the Orion Molecular Cloud (OMC) 2 and 3 filaments, which are bounded by nearby HII regions and which are, therefore, potentially affected by the high-UV illumination of the nearby OB stars. We use various dust parameters to understand whether the small-scale structure (≤1000 au) and the evolutionary status of these solar-type protostars are affected by the nearby HII regions, as is the case for the large-scale (≤104 au) gas chemical composition. Methods. We used the Atacama Large (sub-)Millimeter Array (ALMA) in the 1.3 mm band (246.2 GHz) to image the continuum of 16 young (Class 0/I) OMC-2/3 solar-type protostars, with an angular resolution of 0.25″ (100 au). We completed our data with archival data from the ALMA and VLA VANDAM survey of Orion Protostars at 333 and 32.9 GHz, respectively, to construct the dust SED and extract the dust temperature, the dust emissivity spectral index, the envelope plus disk mass of the sources and to assess whether free-free emission is contaminating their dust SED in the centimetre range. Results. From the millimetre to centimetre range dust SED, we found low dust emissivity spectral indexes (β < 1) for the majority of our source sample and free-free emission towards only 5 of the 16 sample sources. We were also able to confirm or correct the evolutionary status of the source sample reported in the literature. Finally, we did not find any dependence of the source dust parameters on their location in the OMC-2/3 filament. Conclusions. Our results show that the small-scale dust properties of the embedded OMC-2/3 protostars are not affected by the high-UV illumination from the nearby HII regions and that the formation of protostars likely takes place simultaneously throughout the filament.

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Hunting for hot corinos and WCCC sources in the OMC-2/3 filament

Cited by 29 publications

References 74 publications

The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars

The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars

Hot Corinos Chemical Diversity: Myth or Reality?

ORion Alma New GEneration Survey (ORANGES)

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