NOAO > Observing Info > Approved Programs > 2009A-0162
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NOAO > Observing Info > Approved Programs > 2009A-0162 |
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PI: Daniel Caputo, University of Missouri - Columbia, dpce5b@mizzou.edu
Address: Department of Physics and Astronomy, 223 Physics Building UMC,, Columbia MO 65211, United States
CoI: Angela Speck, University of Missouri -Columbia
CoI: Kevin Volk, Gemini Observatory - North
Title: NIRI/Altair imaging of PAH bands around carbon stars: determining the formation and processing mechanisms of organic molecules.
Abstract:
The Unidentified Infrared Bands (UIBs), due to Polycyclic Aromatic
Hydrocarbons (PAHs), are widely observed in the ISM of the Milky Way and
other galaxies of similar metallicity, and 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, actually exhibit UIBs. We propose to obtain NIRI mid-IR imaging
of six C-stars with hot companions, several of which are known to show UIB
emission. We will determine whether UIBs are associated with all binary
C-stars with hot companions, or whether a further criterion is needed. Using
the N-band data still being obtained from program GN-2007B-Q-5 and these
observations we will obtain the 3.3/11.3 micron ratio, which can diagnose the
PAHs size and help discriminate between competing PAH formation hypotheses.
This size information will allow us to constrain the species of the PAHs
being formed. If there is a relationship between the geometry of the system
and a distribution of the sizes of the PAHs then we will be able to provide a
foundational observation for PAH processing.
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 > 2009A-0162 |
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