Open AccessNew models of interstellar gas–grain chemistry – III. Solid CO 2
Author(s) -
Ruffle Deborah P.,
Herbst Eric
Publication year - 2001
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 - 10.1046/j.1365-8711.2001.04394.x
Subject(s) - physics , interstellar cloud , astrochemistry , interstellar medium , diffusion , solid surface , astrophysics , chemical physics , abundance (ecology) , molecular cloud , thermodynamics , stars , galaxy , fishery , biology
Solid CO 2 is observed to be an abundant interstellar ice component towards both quiescent clouds and active star‐forming regions. Our recent models of gas–grain chemistry, appropriate for quiescent regions, severely underproduce solid CO 2 at the single assumed gas density and temperature. In this paper, we investigate the sensitivity of our model results to changes in these parameters. In addition, we examine how the nature of the grain surface affects the results and also consider the role of the key surface reaction between O and CO. We conclude that the observed high abundance of solid CO 2 can be reproduced at reasonable temperatures and densities by models with diffusive surface chemistry, provided that the diffusion of heavy species such as O occurs efficiently.