Shock processing of interstellar nitrogen compounds in the solar nebula

M. E. Kress, S. J. Desch, C. E. Dateo, G. Benedix

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Some organic material in chondrites (primitive meteorites) exhibits a very low 14 N/ 15 N, suggesting that the compounds that carry this heavy nitrogen signature formed in the interstellar medium. Other organic components of the same chondrites show a more solar isotopic signature, suggesting they derive from an isotopically solar reservoir of nitrogen such as N 2 or NH 3 in the solar nebula. In this work, we model the chemistry of the shocks that have been hypothesized as the mechanism to melt chondrules. We find that such shocks (≈ 8 km/s) do not produce significant amounts of HCN and CN if all nitrogen is initially locked in N 2 and all carbon is locked in CO. Only when NH 3 or CH 4 (or both) were present in the initial pre-shock nebula gas do CN and HCN form. We also find that C 2 H 2 (acetylene) and C 2 H form in low abundances if the carbon is all locked in CO in the pre-shock gas. The presence of CH 4 facilitates the formation of acetylene and related compounds. In the absence of CH 4 or NH 3 , only negligible amounts of species containing CΞC or CΞN bonds form. Acetylene and cyanide-related compounds may be precursors to the organics that condensed into meteorites about 4.5 billion years ago. We find that CN bonds largely survive these shocks; thus, the very low interstellar 14 N/ 15 N signature can be preserved if the 15 N is carried by CΞN-bearing interstellar compounds.

Original languageEnglish (US)
Pages (from-to)1473-1480
Number of pages8
JournalAdvances in Space Research
Volume30
Issue number6
DOIs
StatePublished - Sep 2002
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)

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