Organic molecular anions in interstellar and circumstellar environments

被引：3

作者：

Cordiner, M. A. ^{[1
]}

Millar, T. J. ^{[1
]}

Walsh, C. ^{[1
]}

Herbst, E.

Lis, D. C.

Bell, T. A.

Roueff, E.

机构：

[1] Queens Univ Belfast, Sch Math & Phys, Astrophys Res Ctr, Belfast BT7 1NN, Antrim, North Ireland

来源：

IAU: ORGANIC MATTER IN SPACE | 2008年 / 251期

关键词：

Astrochemistry; ISM: molecules; ISM: abundances; ISM: clouds; stars: carbon;

D O I：

10.1017/S1743921308021431

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The synthesis of organic molecular anions in TMC-1 and IRC+10216 is investigated. Modelled C2H-, CN-, C3N-, C5N- and C7N- column densities are sufficiently great that these species might be observable in IRC+10216. Density-enhanced shells in the outer envelope of IRC+10216 are found to enhance the C2H- and CN- column densities by shielding these anions from destruction by UV radiation. From a newly-derived upper column density limit of 6.6x10(10) cm(-2) for C2H- in IRC+10216 we deduce the primary production mechanism for this anion to be C2H2+H- -> C2H- + H-2. In TMC-1, due to the low radiative electron attachment rates calculated for C2H-, CN- and CH2CN-, these species have modelled column densities below the detection threshold. They could, however, be produced in reactions we have not yet considered.

引用

页码：157 / 160

页数：4

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