Timothy J. Arnold, J. A. Eisner, J. D. Monnier, Peter Tuthill
We present spatially resolved observations of the canonical transition disk object TW Hya at 8.74 {\mu}m, 11.66 {\mu}m, and 18.30 {\mu}m, obtained with the T-ReCS instrument on the Gemini telescope. These observations are a result of a novel observing mode at Gemini that enables speckle imaging. Using this technique, we image our target with short enough exposure times to achieve diffraction limited images. We use Fourier techniques to reduce our data, which allows high-precision calibration of the instrumental point spread function. Our observations span two epochs and we present evidence for temporal variability at 11.66 {\mu}m in the disk of TW Hya. We show that previous models of TW Hya's disk from the literature are incompatible with our observations, and construct a model to explain the discrepancies. We detect marginal asymmetry in our data, most significantly at the shortest wavelengths. To explain our data, we require a model that includes an optically thin inner disk extending from 0.02 to 3.9 AU, an optically thick ring representing the outer disk wall at 3.9 AU and extending to 4.6 AU, and a hotter-than-disk-equilibrium source of emission located at ~3.5 AU.
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http://arxiv.org/abs/1204.0550
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