Detection of H3+ in the Diffuse Interstellar Medium Toward Cygnus OB2 No. 12
B. J. McCall,
*
T. R. Geballe,
K. H. Hinkle,
T. Oka
The molecular ion H3+ is considered the
cornerstone of interstellar chemistry because it initiates the
reactions responsible for the production of many larger molecules.
Recently discovered in dense molecular clouds,
H3+ has now been observed in the diffuse
interstellar medium toward Cygnus OB2 No. 12. Analysis of
H3+ chemistry suggests that the high
H3+ column density (3.8 × 1014 per square centimeter) is due not to a high
H3+ concentration but to a long absorption
path. This and other work demonstrate the ubiquity of
H3+ and its potential as a probe of the
physical and chemical conditions in the interstellar medium.
B. J. McCall and T. Oka, Department of Astronomy and
Astrophysics, Department of Chemistry, and the Enrico Fermi Institute,
University of Chicago, Chicago, IL 60637, USA.
T. R. Geballe, Joint Astronomy Centre, University Park, Hilo, HI
96720, USA.
K. H. Hinkle, National Optical Astronomy Observatories, Tucson,
AZ 85726, USA.
*
To whom correspondence should be addressed.
