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Deciphering IR Excess Observed by the Spitzer Space Telescope
in Short Period Interacting Cataclysmic Binaries
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During the first year of the Spitzer Space Telescope Observing Program for Students and Teachers, our team observed a small sample of short orbital period interacting white dwarf binaries. Our scientific investigation was aimed at detection and characterization of the low mass, cool, brown dwarf-like mass donors in these systems. We used the Infrared Array Camera to obtain photometric observations of the polars EF Eri, GG Leo, V347 Pav, and RX J0154.0-5947 at 3.6, 4.5, 5.8, and 8.0 microns. In all our targets, we detected excess emission in the 3-8 micron region over that expected from a brown dwarf alone.
One of the exciting discoveries we made with our IRAC observations is that the star EF Eri was found to be unexpectedly bright in the mid-IR (compared to its 2MASS magnitudes). This fact highlights an opportunity for us to observe EF Eri with the IRS as a follow-up proposal.
We plan to obtain SL1 (7.4-14.5 microns) and SL2 (5.2-8.7 microns) spectroscopy only. We know the IRAC fluxes so our integration times are well constrained and the spectral region covered by SL1, SL2 will yield sufficient S/N to differentiate between cool dust (rising BB like spectrum with PAH and other molecular features allowing us to determine dust size, temperature, and disk extent) and a T type dwarf showing characteristic spectral signatures and a falling Rayleigh-Jeans tail.
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Lead Teacher:
Howard T. Chun
Cranston High School East
Cranston, RI
Participating Teachers:
Linda Stefaniak
Allentown High School, Allentown, NJ
Beth Thomas
East Middle School,
Great Falls, MT
Support Scientists:
Dr. Steve Howell
National Optical Astronomical Observatory, Tucson, AZ
Dr. Don Hoard
Spitzer Science Center, Pasadena, CA
Dr. David Ciardi
Michelson Science Center, Pasadena, CA
Dr. Carolyn Brinkworth
Spitzer Science Center, Pasadena, CA
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Proposal News
Proposal - MS word file
AOR
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