  We present infrared spectra of the binary XX Oph obtained with the Infrared
Spectrograph on the Spitzer Space Telescope. The data show some evidence for
the presence of solid C_60 - the first detection of C_60 in the solid phase -
together with the well-known ``Unidentified Infrared'' emission features. We
suggest that, in the case of XX Oph, the C_60 is located close to the hot
component, and that in general it is preferentially excited by stars having
effective temperatures in the range 15,000-30,000K. C_60 may be common in
circumstellar environments, but un-noticed in the absence of a suitable
exciting source.
