Detection of H3+ in the diffuse interstellar medium: The galactic center and cygnus OB2 number 12

T. R. Geballe, B. J. Mccall, K. H. Hinkle, T. Oka

Research output: Contribution to journalArticlepeer-review

Abstract

Absorption lines of H3+ have been detected in the spectra of two infrared sources in the Galactic center and also toward the heavily reddened star Cygnus OB2 No. 12, whose line of sight is believed to include only diffuse interstellar gas. The absorptions toward the Galactic center sources (IRS 3 and GCS 3-2) probably are due to H3+ both in diffuse gas and in molecular clouds. The ratios of H3+ line equivalent width to extinction toward these three sources are much greater than those toward dense clouds where H3+ has been detected previously. Analysis of the spectra coupled with a simple model for the abundance of H3+ in the diffuse interstellar medium implies that the observed H3+ is present at low densities along long path lengths. These are the first detections of H3+ in the diffuse interstellar medium.

Original languageEnglish (US)
Pages (from-to)251-257
Number of pages7
JournalAstrophysical Journal
Volume510
Issue number1 PART 1
DOIs
StatePublished - Jan 1 1999

Keywords

  • Galaxy: center
  • ISM: clouds
  • ISM: molecules
  • Infrared: ISM: lines and bands
  • Molecular processes
  • Stars: individual (Cygnus OB2 No. 12)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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