Upper limit on C-60 and C-60(+) features in the ISO-SWS spectrum of the reflection nebula NGC 7023

We present here the 7.0-8.7 mu m spectrum of the bright reflection nebula N GC 7023. Our observations are made with the Short Wavelength Spectrometer ( SWS) on the European satellite Infrared Space Observatory (ISO). The vibrat ional bands of the ionized fullerene C-60(+) are expected at 7.11 and 7.51 mu m, while those of the neutral fullerene C-60 are expected at 7.0 and 8.4 5 mu m. We estimate an upper limit in NGC 7023 for the C-60(+) abundance of <0.26% of the interstellar abundance of carbon, while C-60 contains <0.27% of interstellar carbon.