Chemical evolution of cold dark clouds in the vicinity of supernova remnants

Abstract

The supernova explosion increases cosmic ray and x-ray fluxes in the surrounding interstellar medium. Cosmic ray particles and x-ray radiation penetrate nearby molecular clouds and affect the chemical and thermal evolution of the gas. Here we study chemical changes in the dense molecular gas influenced by a sudden increase of the ionization rate that may be caused by the supernova explosion. At the cloud core density $2\times 10^4$ cm${}^{-3}$, the H atom abundance reaches the equilibrium value at about $3\times 10^4$ yr after the change in irradiation conditions. The response time of abundances of icy mantle species is $10^4-10^5$ yr. The abundances of neutral and grain mantle species may not reach their equilibrium values in molecular clouds in the vicinity of 'middle-aged' supernova remnants.

6 pages, 2 figures

References in corpus (3)

• Spitzer spectral line mapping of supernova remnants: I. Basic data and principal component analysis
• Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant
• On the Inference of the Cosmic Ray Ionization Rate $\zeta$ from the HCO${}^{+}$-to-DCO${}^{+}$ Abundance Ratio: The Effect of Nuclear Spin