Detection of C3O in IRC +10216: Oxygen-carbon chain chemistry in the outer envelope

E. D. Tenenbaum, A. J. Apponi, L. M. Ziurys, M. Agúndez, J. Cernicharo, J. R. Pardo, M. Guélin

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28 Scopus citations


The oxygen-bearing species C3O has been identified in the circumstellar envelope of the carbon star IRC +10216. The J = 8 → 7, 9 → 8, 10 → 9, 14 → 13, and 15 → 14 transitions were detected at 2 and 3 mm using the Arizona Radio Observatory's 12 m telescope. Measurements of the J = 9 → 8, 10 → 9, and 12 → 11 lines were simultaneously conducted at the IRAM 30 m telescope. The line profiles of C3O are roughly U-shaped, indicating an extended shell distribution for this molecule in IRC +10216. The total column density derived for C3O is 1.2 × 1012 cm-2, at least an order of magnitude higher than that predicted by current chemical models. However, a revised model that includes reactions of atomic oxygen with carbon-chain radicals, such as 1-C3H and C4, can reproduce the observed abundance. This model also predicts that C3O arises from a shell source with an outer radius near r ∼ 30″, consistent with the observations. These results suggest that gas phase neutral-neutral chemistry may be producing the oxygen-bearing molecules present in the outer envelope of IRC +10216.

Original languageEnglish (US)
Pages (from-to)L17-L20
JournalAstrophysical Journal
Issue number1 II
StatePublished - Sep 20 2006


  • Astrochemistry
  • Circumstellar matter
  • ISM: molecules
  • Radio lines: stars
  • Stars: carbon

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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