Astron. Astrophys. 315, L265-L268 (1996)
The ISO/LWS spectrum of the Egg nebula, AFGL 2688*
P. Cox1,8, E. González-Alfonso2, M.J. Barlow3, X.-W. Liu3, T. Lim4, B.M. Swinyard5, J. Cernicharo6,2, A. Omont7, E. Caux8, C. Gry4,10, M.J. Griffin9, J.-P. Baluteau10, P.E. Clegg9, S. Sidher4, D. Péquignot11, Nguyen-Q-Rieu12, K.J. King5, P.A.R. Ade9, W.A. Towlson3, R.J. Emery5, I. Furniss3, M. Joubert13, C.J. Skinner14, M. Cohen15, C. Armand4, M. Burgdorf4, D. Eward4, A. Di Giorgio4, S. Molinari4, D. Texier4, N. Trams4, S.J. Unger5, W.M. Glencross3, D. Lorenzetti16, B. Nisini16, R. Orfei16, P. Saraceno16, and G. Serra8
1 Institut d'Astrophysique Spatiale, Bât. 120,
Universit'e de Paris XI, F-91405 Orsay, France
Received 15 July 1996 / Accepted 13 September 1996
Abstract. We present an ISO Long Wavelength Spectrometer (LWS) grating spectrum of the carbon-rich proto-planetary nebula AFGL 2688 between 43 and 194 . The far-infrared spectrum of AFGL 2688 is dominated by strong rotational transitions of CO which are detected from J=14-13 up to J=23-22. The atomic fine structure lines [O I] and [C II] are not detected. This is consistent with the cool central star of AFGL 2688 not having yet photodissociated the molecular gas ejected during the AGB phase. The far-infrared CO emission in AFGL 2688 appears to originate in shocked dense gas at a temperature of .
Key words: planetary nebulae: general - planetary nebulae: individual (AFGL 2688) - interstellar medium: molecules
* Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.
Last change: December 16, 1996