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P. Audinos
, C. Kahane
, and R. Lucas
Laboratoire d'Astrophysique de l'Observatoire de Grenoble,
BP 53 X, 414, rue de la Piscine, 38041 Grenoble cedex, France
IRAM, 300, rue de la Piscine, Domaine Universitaire, 38406
Saint-Martin-d'Hères, France.
Abstract: We present sensitive, high
resolution maps of emission in the circumstellar envelope of
IRC+10216. We have mapped the J=16-15, J=18-17 and J=24-23
transitions at 1mm and 2mm wavelength. Contrary to previous maps of
lower transitions, they show centrally peaked intensity
distributions. We resolve this discrepancy by modelling the
vibrational and rotational excitation of , showing that it
largely results from radiative and collisional excitation in the
envelope inner layers. The abundance is changed by this
result in the sense that is more abundant than previously
thought. Our new results are compared with chemical models.
Robert Lucas
Thu Mar 9 14:24:13 MET 1995