DETECTION OF THE SIMPLEST SUGAR, GLYCOLALDEHYDE, IN A SOLAR-TYPE PROTOSTAR WITH ALMA

By J. Jørgensen, C. Favre, S. Bisschop, T. Bourke, E. V. van Dishoeck, M. Schmalzl. 2012

201 citations recorded by the source corpus.

Glycolaldehyde (HCOCH2OH) is the simplest sugar and an important intermediate in the path toward forming more complex biologically relevant molecules. In this Letter we present the first detection of 13 transitions of glycolaldehyde around a solar-type young star, through Atacama Large Millimeter Array (ALMA) observations of the Class 0 protostellar binary IRAS 16293-2422 at 220 GHz (6 transitions) and 690 GHz (7 transitions). The glycolaldehyde lines have their origin in warm (200–300 K) gas close to the individual components of the binary. Glycolaldehyde co-exists with its isomer, methyl formate (HCOOCH3), which is a factor 10–15 more abundant toward the two sources. The data also show a tentative detection of ethylene glycol, the reduced alcohol of glycolaldehyde. In the 690 GHz data, the seven transitions predicted to have the highest optical depths based on modeling of the 220 GHz lines all show redshifted absorption profiles toward one of the components in the binary (IRAS 16293B) indicative of infall and emission at the systemic velocity offset from this by about 0.″2 (25 AU). We discuss the constraints on the chemical formation of glycolaldehyde and other organic species—in particular, in the context of laboratory experiments of photochemistry of methanol-containing ices. The relative abundances appear to be consistent with UV photochemistry of a CH3OH–CO mixed ice that has undergone mild heating. The order of magnitude increase in line density in these early ALMA data illustrates its huge potential to reveal the full chemical complexity associated with the formation of solar system analogs.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9992ca53cf6553d698fcb192e2865eb9f1f49e73

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4. Cecilia Ceccarelli
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Citations in the corpus

• Complex organic molecules in protoplanetary disks (2013, background): “The authors identified several lines of this species in ALMA Science Verification observations of the disk of HD 163296, a Herbig Ae star.”
• Experimental evidence for glycolaldehyde and ethylene glycol formation by surface hydrogenation of CO molecules under dense molecular cloud conditions (2015, background): “Glycolaldehyde has been successfully detected towards the low-mass protostar IRAS 16293–2422 (Jørgensen et al. 2012) with abundances of 6×10−9 relative to H2.”
• Formation of ethylene glycol and other complex organic molecules in star-forming regions (2016, background): “…[EG/GA] ratio seems to increase with the luminosity of the source, from the low values of ∼1 found towards the low-mass protostar IRAS 16293-2422 (Jørgensen et al. 2012 and Jorgensen et al., in prep.) to the higher value of ∼10 towards the hot core G31 and the lower limits of the hot cores in…”
• Grain Surface Models and Data for Astrochemistry (2017, result): “Finally, the correlation found between the abundances of HC(O)CH2OH and H2C(OH)CH2O with those of formaldehyde and methanol is as expected typically in ratios of the order of a few percent and in good agreement with observations (Jørgensen et al. 2012; Schöier et al. 2002).”
• A THREE-PHASE CHEMICAL MODEL OF HOT CORES: THE FORMATION OF GLYCINE (2013, unknown): “Observations of protostellar envelopes, however, do not demonstrate this large abundance of glycolaldehyde; the recent dtection by Jørgensen et al. (2012) toward the Class 0 protostellar binary IRAS 16293-2422, using the ALMA telescope, indicated a HCOOCH3:CH2(OH)CHO ratio of 10 – 15 (although the…”
• Our astrochemical heritage (2012, background): “The obvious question is: why are source A and B so chemically different? They must have had a similar composition of the sublimated ices, as they belong to the same core, so that the difference is probably originating from the different evolutionary status caused by the difference in mass of the two”