NOAO > Observing Info > Approved Programs > 2009B-0535
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NOAO > Observing Info > Approved Programs > 2009B-0535 |
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PI: Daniel Caputo, University of Missouri-Columbia, capput@gmail.com
Address: 223 Physics , University of Missouri-Columbia, Columbia, MO 65211
CoI: Angela Speck, University of Missouri-Columbia
CoI: Kevin Volk, Space Telescope Science Institute
CoI: Mike Barlow, University College London
CoI: Geoff Clayton, Louisiana State University
Title: PAH Formation around Carbon Stars and the Limit of the Hot Companion
Abstract:
The Unidentified Infrared Bands (UIBs), believed to be due to PAHs, often
dominate Spitzer mid-IR images of galaxies. Carbon stars (C-stars) are
frequently cited as the source of PAHs, although only a very small number of
C-stars, all with hot companions, have been shown to exhibit UIBs. We propose
to obtain Michelle mid-IR narrow-band imaging and R=200 long-slit spectra of
eight C-stars with companions ranging from A- to K-type, which could show
spatially resolved UIB emission. We have had success with a previous program
wherein the 11.3 UIB was found for the first time around SZ Sgr, which were
not detected by ISO. With this data we will be able to determine whether UIBs
are associated with all binary C-stars with hot companions, or whether a
further criterion is needed. The spectro-imaging of C-stars whose companions
have differing separations and effective temperatures will allow us to
determine how the UIB emission depends on the intensity and hardness of the
UV irradiation. This, together with the observed band ratios, can diagnose
whether the PAHs are small or large and help discriminate between competing
PAH formation hypotheses.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2009B-0535 |
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