1 Centre for Star and Planet Formation, Niels Bohr Institute and Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5–7, 1350 Copenhagen K, Denmark
2 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
Received: 8 December 2014
Accepted: 30 January 2015
Glycolaldehyde is a key molecule in the formation of biologically relevant molecules such as ribose. We report its detection with the Plateau de Bure interferometer toward the Class 0 young stellar object NGC 1333 IRAS2A, which is only the second solar-type protostar for which this prebiotic molecule is detected. Local thermodynamic equilibrium analyses of glycolaldehyde, ethylene glycol (the reduced alcohol of glycolaldehyde), and methyl formate (the most abundant isomer of glycolaldehyde) were carried out. The relative abundance of ethylene glycol to glycolaldehyde is found to be ~5 – higher than in the Class 0 source IRAS 16293-2422 (~1), but similar to the lower limits derived in comets (≥3–6). The different ethylene glycol-to-glycolaldehyde ratios in the two protostars might be related to different CH3OH:CO compositions of the icy grain mantles. In particular, a more efficient hydrogenation on the grains in NGC 1333 IRAS2A would favor the formation of both methanol and ethylene glycol. In conclusion, it is possible that like NGC 1333 IRAS2A, other low-mass protostars show high ethylene glycol-to-glycolaldehyde abundance ratios. The cometary ratios might consequently be inherited from earlier stages of star formation if the young Sun experienced conditions similar to NGC 1333 IRAS2A.
Key words: astrochemistry / astrobiology / ISM: individual objects: NGC 1333 IRAS2A / stars: formation / stars: protostars / ISM: molecules
Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Figures 3–4 and Table 1 are available in electronic form at http://www.aanda.org
© ESO, 2015