Observations of the (1,0) vibrational band of interstellar CN toward zeta ophiuchi

David M. Meyer*, Katherine C. Roth

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We have obtained very high signal-to-noise ratio (S/N) (≈1200), high-resolution (0.05 Å) observations of the 3580 A spectral region toward ζ Oph in an effort to detect the weak R(0) line corresponding to the (1,0) vibrational band of interstellar CN. Our measurement of 0.67 ± 0.06 mÅ for the CN (1,0) R(0) line strength indicates a J = 0 column density which is consistent with earlier determinations from the much stronger (0,0) R(0) line and the assumption of a single-component line profile. This finding implies that the complex velocity structure evident from CO radio observations of the ζ Oph line of sight does not seriously complicate the saturation corrections for the CN lines. Consequently, the accurate measurements of the cosmic microwave background temperature previously determined through the rotational excitation of CN toward ζ Oph are safe in this respect. Our ζ Oph observations also reveal an equivalent width of 2.14 ± 0.08 mÅ for the (3,0) R(0) line of interstellar 12CH+ at 3579.02 Å along with strong evidence of Cr I λ3578.69 absorption. The 12CH+ measurement yields a higher column density than expected from previous observations of the stronger (0,0) and (1,0) vibrational bands. The electron density indicated by the Cr ionization balance is consistent with determinations of ne from other atoms in the ζ Oph cloud.

Original languageEnglish (US)
Pages (from-to)91-96
Number of pages6
JournalAstrophysical Journal
Issue number1
StatePublished - Jan 20 1990


  • Cosmic background radiation
  • Interstellar: abundances
  • Interstellar: molecules
  • Stars: individual (ζ Oph)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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