Open AccessThe chemistry of transient microstructure in the diffuse interstellar medium
Author(s) -
Bell T. A.,
Viti S.,
Williams D. A.,
Crawford I. A.,
Price R. J.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.08693.x
Subject(s) - microstructure , physics , interstellar medium , astrophysics , extinction (optical mineralogy) , transient (computer programming) , molecular cloud , interstellar cloud , astrochemistry , chemical physics , molecular physics , galaxy , optics , chemistry , crystallography , stars , computer science , operating system
Transient microstructure in the diffuse interstellar medium (ISM) has been observed towards Galactic and extragalactic sources for decades, usually in lines of atoms and ions, and, more recently, in molecular lines. Evidently, there is a molecular component to the transient microstructure. In this paper, we explore the chemistry that may arise in such microstructure. We use a photodissociation region (PDR) code to model the conditions of relatively high density, low temperature, very low visual extinction and very short elapsed time that are appropriate for these objects. We find that there is a well‐defined region of parameter space where detectable abundances of molecular species might be found. The best matching models are those where the interstellar microstructure is young (<100 yr), small (∼100 au) and dense (>10 4 cm −3 ) .