| Autor: |
Loison, Jean-Christophe, Agúndez, Marcelino, Wakelam, Valentine, Roueff, Evelyne, Gratier, Pierre, Marcelino, Núria, Reyes, Dianailys Nuñez, Cernicharo, José, Gerin, Maryvonne |
| Předmět: |
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| Zdroj: |
Monthly Notices of the Royal Astronomical Society; Oct2017, Vol. 470 Issue 4, p4075-4088, 14p |
| Abstrakt: |
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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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