Upper limit on C 60 and C + 60 features in the ISO - SWS spectrum of the reflection nebula NGC 7023 ⋆
نویسندگان
چکیده
We present here the 7.0–8.7 μm spectrum of the bright reflection nebula NGC 7023. Our observations are made with the Short Wavelength Spectrometer (SWS) on the European satellite Infrared Space Observatory (ISO). The vibrational bands of the ionized fullerene C60 are expected at 7.11 and 7.51 μm, while those of the neutral fullerene C60 are expected at 7.0 and 8.45 μm. We estimate an upper limit in NGC 7023 for the C60 abundance of <0.26% of the interstellar abundance of carbon, while C60 contains <0.27% of interstellar carbon.
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