Understanding the chemical complexity in Circumstellar Envelopes of C-Rich AGB stars: The case of IRC +10216

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

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The circumstellar envelopes of carbon-rich AGB stars show a chemical complexity that is exemplified by the prototypical object IRC +10216, in which about 60 different molecules have been detected to date. Most of these species are carbon chains of the type C n H, C n H 2 , C n N, HC n N. We present the detection of new species (CH 2 CHCN, CH 2 CN, H 2 CS, CH 3 CCH and C 3 O) achieved thanks to the systematic observation of the full 3 mm window with the IRAM 30m telescope plus some ARO 12m observations. All these species, known to exist in the interstellar medium, are detected for the first time in a circumstellar envelope around an AGB star. These five molecules are most likely formed in the outer expanding envelope rather than in the stellar photosphere. A pure gas phase chemical model of the circumstellar envelope is reasonably successful in explaining the derived abundances, and additionally allows to elucidate the chemical formation routes and to predict the spatial distribution of the detected species.

Original languageEnglish (US)
Pages (from-to)229-233
Number of pages5
JournalAstrophysics and Space Science
Issue number1-3
StatePublished - Jan 2008


  • AGB stars
  • Astrochemistry
  • Circumstellar matter
  • IRC +10216
  • Molecular processes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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