Chemical modelling of glycolaldehyde and ethylene glycol in star-forming regions

Audrey Coutens 1 S. Viti 2 J. M. C. Rawlings M. T. Beltrán J. Holdship I. Jiménez-Serra D. Quenard 3 V. M. Rivilla 4
1 AMOR 2018
LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
2 Atmospheric Physics Laboratory [UCL London]
3 CSTB Saint Martin d'Hères - Centre Scientifique et Technique du Bâtiment
4 CAB - Centro de Astrobiologia [Madrid]
Abstract : Glycolaldehyde (HOCH$_2$CHO) and ethylene glycol ((CH$_2$OH)$_2$) are two complex organic molecules detected in the hot cores and hot corinos of several star-forming regions. The ethylene glycol/glycolaldehyde abundance ratio seems to show an increase with the source luminosity. In the literature, several surface-chemistry formation mechanisms have been proposed for these two species. With the UCLCHEM chemical code, we explored the different scenarios and compared the predictions for a range of sources of different luminosities with the observations. None of the scenarios reproduce perfectly the trend. A better agreement is, however, found for a formation through recombination of two HCO radicals followed by successive hydrogenations. The reaction between HCO and CH$_2$OH could also contribute to the formation of glycolaldehyde in addition to the hydrogenation pathway. The predictions are improved when a trend of decreasing H$_2$ density within the core region with T $\geq$ 100 K as a function of luminosity, is included in the model. Destruction reactions of complex organic molecules in the gas phase would also need to be investigated, since they can affect the abundance ratios once the species have desorbed in the warm inner regions of the star-forming regions.
Keywords : Astrophysics - Solar and Stellar Astrophysics Astrophysics - Astrophysics of Galaxies
Type de document :
Article dans une revue
Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2018, 475 (2), pp.2016-2026
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https://hal.archives-ouvertes.fr/hal-01685039
Contributeur : Marie-Paule Pomies <>
Soumis le : mardi 16 janvier 2018 - 08:28:37
Dernière modification le : jeudi 16 août 2018 - 09:24:01

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Audrey Coutens, S. Viti, J. M. C. Rawlings, M. T. Beltrán, J. Holdship, et al.. Chemical modelling of glycolaldehyde and ethylene glycol in star-forming regions. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2018, 475 (2), pp.2016-2026. 〈hal-01685039〉

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