The interstellar 4.62 micron band

YJ Pendleton*, AGGM Tielens, AT Tokunaga, MP Bernstein

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

We present new 4.5-5.1 mu m (2210-1970 cm(-1)) spectra of embedded protostars, W33 A, AFGL 961 E, AFGL 2136, NGC 7538 IRS 9, and Mon R2 IRS 2, which contain a broad absorption feature located near 4.62 mu m (2165 cm(-1)), commonly referred to in the literature as the "X-C=N" band. The observed peak positions and widths of the interstellar band agree to within 2.5 cm(-1) and 5 cm(-1), respectively. The strengths of the interstellar 4.62 mu m band and the ice absorption features in these spectra are not correlated, which suggests a diversity of environmental conditions for the ices we are observing. We explore several possible carriers of the interstellar band and review possible production pathways through far-ultraviolet photolysis (FUV), ion bombardment of interstellar ice analog mixtures, and acid-base reactions. Good fits to the interstellar spectra are obtained with an organic residue produced through ion bombardment of nitrogen-containing ices or with the OCN(-) ion produced either through acid-base reactions or FUV photolysis of NH(3)-containing ices.

Original languageEnglish
Pages (from-to)294-304
Number of pages11
JournalAstrophysical Journal
Volume513
Issue number1
Publication statusPublished - 1-Mar-1999

Keywords

  • infrared : ISM : lines and bands
  • ISM : clouds
  • ISM : molecules
  • line : identification
  • stars : pre-main-sequence
  • ASTROPHYSICAL ICE ANALOGS
  • MAIN-SEQUENCE STARS
  • TAURUS DARK CLOUD
  • INFRARED-SPECTROSCOPY
  • GRAIN MANTLES
  • ABSORPTION FEATURES
  • MOLECULAR CLOUDS
  • SOLID CO
  • XCN BAND
  • SPECTRA

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