Widespread Presence of Glycolaldehyde and Ethylene Glycol around Sagittarius B2

Li, Juan; Shen, Zhi-Qiang; Wang, Junzhi; Chen, Xi; Li, Di; Wu, Yajun; Dong, Junping; Zhao, Rong-Bing; Gou, Weiping; Wang, Jinqing; Li, Shanghuo; Wang, Bingru; Zheng, Xingwu

doi:10.3847/1538-4357/aa9069

Cited by 28 publications

(33 citation statements)

References 58 publications

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“…They suggested that CH 2 (OH)CHO was much more extended compared to CH 3 OCHO and its emission was spatially filtered by the interferometric character of the observations. These findings are supported by the more recent study of Li et al (2017) towards an extended region of the Galactic Centre in which the authors reported cold gas emission of CH 2 (OH)CHO ∼36 pc in width around Sgr B2(N). We note that, these two observations of the CH 2 (OH)CHO spatial extent are specific to the Galactic Centre, where non-thermal desorption processes put the CH 2 (OH)CHO in the gas phase at temperatures much lower than the thermal desorption temperature of this species.…”

Section: Spatial Extentsupporting

confidence: 78%

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

Manigand

Jørgensen

Calcutt

et al. 2020

A&A

132

154

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Context. Complex organic molecules are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these species form remains an open question.Aims. This study aims to constrain the formation of complex organic molecules through comparisons of their abundances towards the Class 0 protostellar binary IRAS 16293-2422. Methods. We utilised observations from the Atacama Large Millimetre/submillimetre Array (ALMA) Protostellar Interferometric Line Survey (PILS) of IRAS 16293-2422. The species identification and the rotational temperature and column density estimation were derived by fitting the extracted spectra towards IRAS 16293-2422 A and IRAS 16293-2422 B with synthetic spectra. The majority of the work in this paper pertains to the analysis of IRAS 16293-2422 A for a comparison with the results from the other binary component, which have already been published. Results. We detect 15 different complex species, as well as 16 isotopologues towards the most luminous companion protostar IRAS 16293-2422 A. Tentative detections of an additional 11 isotopologues are reported. We also searched for and report on the first detections of methoxymethanol (CH 3 OCH 2 OH) and trans-ethyl methyl ether (t-C 2 H 5 OCH 3 ) towards IRAS 16293-2422 B and the follow-up detection of deuterated isotopologues of acetaldehyde (CH 2 DCHO and CH 3 CDO). Twenty-four lines of doubly-deuterated methanol (CHD 2 OH) are also identified. Conclusions. The comparison between the two protostars of the binary system shows significant differences in abundance for some of the species, which are partially correlated to their spatial distribution. The spatial distribution is consistent with the sublimation temperature of the species; those with higher expected sublimation temperatures are located in the most compact region of the hot corino towards IRAS 16293-2422 A. This spatial differentiation is not resolved in IRAS 16293-2422 B and will require observations at a higher angular resolution. In parallel, the list of identified CHD 2 OH lines shows the need of accurate spectroscopic data including their line strength. Article number, page 2 of 31 S. Manigand et al.: Inventory of complex organic molecules towards IRAS 16293-2422 A Notes. (a) e 0 , o 1 and e 1 corresponds to the three first torsional states. The notation of the quantum numbers is directly taken from Mukhopadhyay (2016). (b) This corresponds to the number indicated in the top-right corner of each panel in Figures D.1 and D.2. (c) W is the integrated intensity of the unblended lines, summed over the range [ν 0 − ∆ν FWHM , ν 0 + ∆ν FWHM ], given ∆ν FWHM = ν 0 FWHM c , with FWHM equal to 2.2 and 0.8 km s −1 for IRAS 16293A and B, respectively.

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Section: Spatial Extentsupporting

confidence: 78%

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

Manigand

Jørgensen

Calcutt

et al. 2020

A&A

132

154

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“…Most of these reactions have been studied experimentally in various ways (Fedoseev et al 2015;Butscher et al 2015;Chuang et al 2016;Fedoseev et al 2017;Chuang et al 2017;Butscher et al 2017) and they have also been proposed by and are included in a number of astrochemical model studies (Garrod et al 2008;Woods et al 2012;Coutens et al 2018). Similar conclusions are also supported by observational work for specific species (Rivilla et al 2017;Li et al 2017). Despite this significant amount of investigations, relatively little is known about the reaction rate constants at low temperature, while these are the crucial parameters needed to constrain modeling studies.…”

Section: Introductionsupporting

confidence: 65%

Hydrogen transfer reactions of interstellar complex organic molecules

Álvarez‐Barcia

Russ

Kästner

et al. 2018

Monthly Notices of the Royal Astronomical Society

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Radical recombination has been proposed to lead to the formation of complex organic molecules (COMs) in CO-rich ices in the early stages of star formation. These COMs can then undergo hydrogen addition and abstraction reactions leading to a higher or lower degree of saturation. Here, we have studied 14 hydrogen transfer reactions for the molecules glyoxal, glycoaldehyde, ethylene glycol, and methylformate and an additional three reactions where CH n O fragments are involved. Over-the-barrier reactions are possible only if tunneling is invoked in the description at low temperature. Therefore the rate constants for the studied reactions are calculated using instanton theory that takes quantum effects into account inherently. The reactions were characterized in the gas phase, but this is expected to yield meaningful results for CO-rich ices due to the minimal alteration of reaction landscapes by the CO molecules.We found that rate constants should not be extrapolated based on the height of the barrier alone, since the shape of the barrier plays an increasingly larger role at decreasing temperature. It is neither possible to predict rate constants based only on considering the type of reaction, the specific reactants and functional groups play a crucial role. Within a single molecule, though, hydrogen abstraction from an aldehyde group seems to be always faster than hydrogen addition to the same carbon atom. Reactions that involve heavy-atom tunneling, e.g., breaking or forming a C-C or C-O bond, have rate constants that are much lower than those where H transfer is involved.

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“…The 89 GHz transitions with a higher upper-level energy (26.43 K) are regarded as coming from the 'warm' phase, while transitions with a lower upper-level energy (1.2 K) are regarded as coming from the 'cold' phase. The 'cold' glycolaldehyde was found to be widespread around the Sgr B2 complex (Li et al 2017). Fig.…”

Section: Speciesmentioning

confidence: 99%

“…Many COMs are first detected toward Sgr B2(N), such as glycoaldehyde CH 2 OHCHO (Hollis, Lovas & Jewell 2000), ethylene glycol HOCH 2 CH 2 OH (Hollis, Lovas & Jewell 2002), amino acetonitrile H 2 NCH 2 CN (Belloche et al 2008) and so on. Some COMs, such as glycolaldehyde and ethylene glycol, were found to be widespread in the Galactic centre (Hollis et al 2001;Requena-Torres et al 2006, 2008Li et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Mapping observations of complex organic molecules around Sagittarius B2 with the ARO 12 m telescope

Wang

Qiao

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We have performed high-sensitivity mapping observations of several complex organic molecules around Sagittarius B2 with the ARO 12 m telescope at 3 mm wavelength. Based on their spatial distribution, molecules can be classified as either ‘extended’, those detected not only in Sgr B2(N) and Sgr B2(M), or ‘compact’, those only detected toward or near Sgr B2(N) and Sgr B2(M). The ‘extended’ molecules include glycolaldehyde (CH2OHCHO), methyl formate (CH3OCHO), formic acid (t-HCOOH), ethanol (C2H5OH) and methyl amine (CH3NH2), while the ‘compact’ molecules include dimethyl ether (CH3OCH3), ethyl cyanide (C2H5CN), and amino acetonitrile (H2NCH2CN). These ‘compact’ molecules are likely produced under strong UV radiation, while the ‘extended’ molecules are likely formed at low temperatures, via gas-phase or grain-surface reactions. The spatial distribution of ‘warm’ CH2OHCHO at 89 GHz differs from the spatial distribution of ‘cold’ CH2OHCHO observed at 13 GHz. We found evidence for an overabundance of CH2OHCHO compared to that expected from the gas-phase model, which indicates that grain-surface reactions are necessary to explain the origin of CH2OHCHO in Sagittarius B2. Grain-surface reactions are also needed to explain the correlation between the abundances of ‘cold’ CH2OHCHO and C2H5OH. These results demonstrate the importance of grain-surface chemistry in the production of complex organic molecules.

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Widespread Presence of Glycolaldehyde and Ethylene Glycol around Sagittarius B2

Cited by 28 publications

References 58 publications

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

Hydrogen transfer reactions of interstellar complex organic molecules

Mapping observations of complex organic molecules around Sagittarius B2 with the ARO 12 m telescope

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