Program: GS-2012A-Q-13

I propose to test the feasibility of a differential photometric technique to identify faint dusty circumstellar debris disks with excess ten-micron silicate emission. A small number of perhaps the brightest such disks have been discovered by Spitzer and in archival IRAS data. These point to the potential existence of numerous other analogs of the solar system zodiacal dust belt. Silicate emission at $\sim$10$\micron$ is a distinctive feature of the excess signature of exozodiacal belts. The proposed technique employs differential narrow-band 8--11$\micron$ photometry across the silicate feature, repeatedly sampling its 10--11$\micron$ peak and its $<$9$\micron$ low-flux wing. This is a re-submission of a classically scheduled one-night 2011B program on Gemini South, that was 65\% lost to clouds and telescope faults. The one classical night did, however, allow me to refine the observational approach. I now request 21hrs of queue-scheduled time on either Gemini North or South. Eightieth percentile sky transparency at Mauna Kea (50\%-ile at Cerro Pachon) is sufficient for the technique to work as well as exozodi searches with Spitzer around G stars within 25pc.