The ISO LWS grating spectrum of NGC7027

X.-W. Liu - M. J. Barlow - Nguyen-Q-Rieu - Truong-Bach - P. Cox - D. Péquignot - P. E. Clegg - B. M. Swinyard - M. J. Griffin - J. P. Baluteau - T. Lim 8 - C. J. Skinner - H. A. Smith - P. A. R. Ade - I. Furniss - W. A. Towlson - S. J. Unger - K. J. King - G. R. Davis - M. Cohen - R. J. Emery - J. Fischer - W. M. Glencross - E. Caux - M. A. Greenhouse - C. Gry - M. Joubert - D. Lorenzetti - B. Nisini - A. Omont - R. Orfei - P. Saraceno - G. Serra - H. J. Walker - C. Armand - M. Burgdorf - A. Di Giorgio - S. Molinari - M. Price - D. Texier - S. Sidher - N. Trams

Abstract:

We present a high signal-to-noise ISO Long Wavelength Spectrometer (LWS) grating spectrum of the planetary nebula NGC7027 from 43-194 microns. In total 40 emission lines have been detected, with 30 identified. From the ionized region, we observe fine-structure lines from [N II], [N III] and [O III]. The [O I] and [C II] fine-structure lines from the photodissociation region are the strongest features observed in this spectral region. Amongst the molecular lines, 11 pure rotation CO lines from J=14-13 up to J=24-23 have been detected. The most striking result, however, is the detection in this carbon-rich nebula of the o-H₂O 179.53 micron and the OH 119.3 micron fundamental lines. Astrophysical implications are briefly discussed.

Keywords:
planetary nebulae: general - planetary nebulae: individual: NGC7027 - ISM: atoms - ISM: molecules

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