Detection of glycolaldehyde towards the solar-type protostar NGC1333 IRAS2A

TL;DR

This study reports the detection of glycolaldehyde, a prebiotic molecule, in a solar-type protostar, revealing insights into the chemical complexity of star-forming regions and potential inheritance of organic molecules by comets.

Contribution

First detection of glycolaldehyde in NGC1333 IRAS2A, a solar-type protostar, with analysis of its abundance ratios providing clues about chemical processes in star formation.

Findings

Glycolaldehyde detected in NGC1333 IRAS2A, only the second such detection in a solar-type protostar.

The ethylene glycol to glycolaldehyde ratio is higher than in some other protostars, suggesting different chemical pathways.

Possible inheritance of organic molecule ratios from star-forming regions to comets.

Abstract

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 towards the Class 0 young stellar object NGC1333 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 comparable to the lower limits derived in comets ($\geq$3-6). The different ethylene glycol-to-glycolaldehyde ratios in the two protostars could 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 could consequently be inherited from earlier stages of star formation, if the young Sun experienced conditions similar to NGC1333 IRAS2A.