We report spectrophotometric observations made with SOFIA/FORCAST on 2011 June 2 UT. Optical measurements have previously shown that the abundance discrepancy factor (adf) varies with position in several high-adf PNe, and is highest close to the central star. The very low electron temperature inclusions postulated to explain the abundance discrepancy, must be cooled predominantly by fine structure IR lines. These SOFIA data will map mid-IR FS lines (and our related Herschel program will add several far-IR FS lines) in the bright, well-characterized, high-adf PN NGC 7009. We will compare these IR results with FS optical line measurements in order to correlate ratios of IR to optical fluxes with position, and thus correlate with where the adf peaks.

We present very deep spectroscopic observations of the rich optical recombination line (ORL) spectrum of the bright Saturn nebula NGC 7009. Detailed spectral analyses, combined with systematic emission line identifications, in the whole optical range (3040–11 000 Å) give more than 1000 emission lines, over 80% of which are ORLs. New calculations of the N ii effective recombination coefficients in intermediate coupling scheme are carried out. These N ii atomic data, together with the most recent O ii and Ne ii effective recombination coefficients, are utilized in the spectral analyses of NGC 7009. Departure from LS coupling is noticed. Agreement is found between the observed and predicted relative intensities of ORLs. The elemental abundances of C, N, O, and Ne deduced from ORLs are systematically higher than those from collisionally excited lines (CELs) by a factor of 5–7.

We developed a self-consistent stellar-nebular model for NGC 7009. This model reproduces the available observations ranging from optical to UV. The combined approach to the modeling process produces more constraints and thus more trustworty results. After obtaining the model, we perform a comparative study of the chemical composition of He, N, O, Ne, Cl, and S in the nebula and its central star. Concluding that the stellar composition agrees with the nebular composition with t2 ≠ 0.00.

The high-excitation planetary nebula NGC 7009 and its central star were observed with the Far Ultraviolet Spectroscopic Explorer (FUSE) through a 30$\,{\times}\,$30 arcsec (LWRS) aperture, and with the HIRS narrow slit (1.25$\,{\times}\,$20 arcsec) to isolate the inner and outer parts of the nebula from the central star. The high-resolution (15 km/s) nebular spectra (910-1187 Å) show strong emission from C III] and permitted transitions of He II N II, N III, S III, S IV, S VI and O VI, with stronger emission closer to the central star. In this paper we present results obtained on the spatial variation of these tracers of highly ionized gas. The hot central star of NGC 7009 is discussed in a separate paper by Sonneborn et al.

High-resolution 905-1187Å spectra of the central star of NGC 7009 obtained with the FUSE satellite provide new constraints on the mass loss and atmosphere parameters. The most prominent spectral feature is a very strong P-Cygni profile of O VI 1032-1038. The only other wind lines are S VI 933-44 (FUSE) and N V 1238-42 and O V 1371 from IUE spectra. C IV 1548-50 and P V 1118-28 are not present, indicating that the wind is very highly ionized. A lower limit on the mass loss rate ($\dot{M}>10^{-8} M_{\odot} $y$^{-1}, v_{\infty}=2450$ km s$^{-1}$) has been derived from an SEI analysis of these wind lines. Preliminary identification of several photospheric spectral features include several strong Fe VII and O VI lines between 1100 and 1170 Å.