HD/H2 ratio in the diffuse interstellar medium

被引：12

作者：

Balashev, S. A. ^{[1
]}

Kosenko, D. N. ^{[1
]}

机构：

[1] Ioffe Inst, 26 Politekn Skaya St, St Petersburg 194021, Russia

来源：

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | 2020年 / 492卷 / 01期

关键词：

ISM: abundances; cosmic rays; ISM: molecules; quasars: absorption lines; COSMIC-RAY IONIZATION; HIGH-REDSHIFT; PHYSICAL CONDITIONS; ABSORPTION SYSTEM; MOLECULAR CLOUDS; HD MOLECULES; DLA SYSTEM; H-2; GAS; DEUTERIUM;

D O I：

10.1093/mnrasl/slz180

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present a semi-analytical description of the relative hydrogen deuteride (HD)/H-2 abundance in the diffuse interstellar medium. We found three asymptotics of the relative HD/H-2 abundance for different parts of the medium and their dependence on the physical parameters, namely, number density, intensity of the ultraviolet field, cosmic ray ionization rate, and metallicity. Our calculations are in a good agreement with the full network calculations using MEUDON PDR code. We found that in the case of low metallicity and/or higher cosmic ray ionization rate, HD formation rate is significantly enhanced, HD/H-2 ratio increases, and the D-I/HD transition occurs at lower penetration depth of ultraviolet radiation than the HD/H-2 transition. This can explain the observed difference in the HD/H-2 abundance between the local and high-redshift measurements.

引用

页码：L45 / L49

页数：5

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