2006ApJ...637L..45J

We report spectra obtained with the Spitzer Space Telescope in the λ = 5-35 µm range of HD 233517, an evolved K2 III giant with circumstellar dust. For λ > 13 µm, the flux is a smooth continuum that varies approximately as ν^–5/3. For λ < 13 µm, although the star is oxygen-rich, PAH features produced by carbon-rich species at 6.3, 8.2, 11.3, and 12.7 µm are detected along with likely broad silicate emission near 20 µm. These results can be explained if there is a passive, flared disk orbiting HD 233517. Our data support the hypothesis that organic molecules in orbiting disks may be synthesized in situ as well as having been incorporated from the interstellar medium.