The effect of varying cosmic ray ionization rates on dark cloud chemistry

P. R.A. Farquhar, T. J. Millar, Eric Herbst

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


We investigate the effects of varying the cosmic ray ionization rate in chemical models of dense interstellar clouds. In the absence of such ionization, a scenario which may be applicable to dark cloud cores, we find that chemi-ionization is able to drive a limited ion-neutral chemistry. Models of clouds in starburst galaxies, which may have enhanced cosmic ray fluxes, are also investigated and enable an upper limit to be derived for the cosmic ray ionization rate in M82. The derived value, which is about 700 times the typical value for Galactic molecular clouds, is in good agreement with that necessary to explain the recent observations of C I in this galaxy.

Original languageEnglish
Pages (from-to)641-648
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 01 Jan 1994
Externally publishedYes


  • Abundances
  • Clouds - cosmic rays - ISM
  • Molecular processes - ISM
  • Molecules -galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The effect of varying cosmic ray ionization rates on dark cloud chemistry'. Together they form a unique fingerprint.

Cite this