H3+ in dense and diffuse clouds

Benjamin J. McCall, Kenneth H. Hinkle, Thomas R. Geballe, Takeshi Oka

Research output: Contribution to journalArticlepeer-review


Interstellar H3+ has been detected in dense as well as diffuse clouds using three 3.7 μm infrared spectral lines of the ν2 fundamental band. Column densities of H3+ from (1.7-5.5) × 1014 cm-2 have been measured in dense clouds in absorption against the infrared continua of the deeply embedded young stellar objects GL2136, W33A, MonR2 1RS 3, GL961E, and GL2591. Strong and broad H3+ absorptions have been detected in dense and diffuse clouds towards GC 1RS 3 and GCS3-2 in the region of the galactic center. A large column density of H3+, comparable to that of a dense cloud, has been detected towards the visible star Cygnus OB2 No. 12, which has a line of sight that crosses mostly diffuse clouds. The H3+ chemistry of dense and diffuse clouds are discussed using a very simple model. Some future projects and problems are discussed.

Original languageEnglish (US)
Pages (from-to)267-280
Number of pages14
JournalFaraday Discussions
StatePublished - 1998

ASJC Scopus subject areas

  • General Medicine


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