LOISON, Jean-Christophe; MARCELINO, Marcelino; WAKELAM, Valentine; ROUEFF, Evelyne; GRATIER, P.; MARCELINO, Núria; REYES, Dianailys Nuñez; CERNICHARO, José; GERIN, Maryvonne; AGÚNDEZ, Marcelino

doi:10.1093/mnras/stx1265

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LOISON, Jean-Christophe
Institut des Sciences Moléculaires [ISM]

MARCELINO, Marcelino
Departamento de Engenharia Informática / Department of Informatics Engineering [DEI]

WAKELAM, Valentine
AMOR 2017

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Article de revue

Ce document a été publié dans

Monthly Notices of the Royal Astronomical Society. 2017-10, vol. 470, n° 4, p. 4075 - 4088

Oxford University Press (OUP): Policy P - Oxford Open Option A

Résumé en anglais

We report the detection of linear and cyclic isomers of C3H and C3H2 towards various starless cores and review the corresponding chemical pathways involving neutral (C3Hx with x = 1,2) and ionic (C3Hx+ with x = 1,2,3) isomers. We highlight the role of the branching ratio of electronic dissociative recombination (DR) reactions of C3H2+ and C3H3+ isomers, showing that the statistical treatment of the relaxation of C3H* and C3H2* produced in these DR reactions may explain the relative c,l-C3H and c,l-C3H2 abundances. We have also introduced in the model the third isomer of C3H2 (HCCCH). The observed cyclic-to-linear C3H2 ratio varies from 110 ± 30 for molecular clouds with a total density of about 1 × 104 molecules cm-3 to 30 ± 10 for molecular clouds with a total density of about 4 × 105 molecules cm-3, a trend well reproduced with our updated model. The higher ratio for molecular clouds with low densities is determined mainly by the importance of the H + l-C3H2 → H + c-C3H2 and H + t-C3H2 → H + c-C3H2 isomerization reactions.< Réduire

Mots clés en anglais

astrochemistry

ISM: abundances

ISM: clouds

ISM: molecules

DOI

http://dx.doi.org/10.1093/mnras/stx1265

Project ANR

Molecules interstellaires : spectroscopie et synthèse en laboratoire - ANR-13-BS05-0008

Origine

Importé de hal

Unités de recherche

Laboratoire d'Astrophysique de Bordeaux (LAB) - UMR 5804