Paper: astro-ph/0512371
Date: Wed, 14 Dec 2005 18:29:41 GMT (49kb)

Title: Polycyclic Aromatic Hydrocarbons Orbiting HD 233517, an Evolved
Oxygen-Rich Red Giant

Authors: M. Jura (UCLA), J. Bohac, B. Sargent, W. J. Forrest, J. Green, D. M.
Watson (Rochester), G. C. Sloan (Cornell), F. Markwick-Kemper (Virginia), C.
H. Chen, J. Najita (NOAO)

Comments: 11 pages, 2 figures, ApJ Letters, in press
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We report spectra obtained with the Spitzer Space Telescope in the 5 to 35
micron range of HD 233517, an evolved K2 III giant with circumstellar dust. At
wavelengths longer than 13 microns, the flux is a smooth continuum that varies
approximately as frequency to the -5/3 power. For wavelengths shorter than 13
microns, although the star is oxygen-rich, PAH features produced by carbon-rich
species at 6.3 microns, 8.2 microns, 11.3 microns and 12.7 microns are detected
along with likely broad silicate emission near 20 microns. 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 being incorporated from the interstellar medium.

\\ ( http://arXiv.org/abs/astro-ph/0512371 , 49kb)