Planetary Collisions in a Binary Star System? Studying the Evolution of Warm Dust Encircling BD +20 307 Using SOFIA
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Maggie Thompson
University of California, Santa Cruz
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The small class of known stars with unusually warm, dusty debris disks is a key sample to probe in order to understand cascade models and the extreme collisions that likely lead to the final configurations of planetary systems. Because of its extreme dustiness and small radius, the disk around the binary star system BD +20 307 has a short predicted collision time and is therefore an interesting target in which to look for changes in dust quantity and composition over time. In this talk, I will discuss our recent work comparing SOFIA photometry and spectroscopy observations to previous ground and space-based data spanning over the course of ~10 years. In addition to an overall increase (~10%) in infrared excess (8.8-12.5 μm), there is a suggestion of a greater increase in flux at shorter wavelengths (less than 10.6 μm) compared to longer wavelengths (greater than 10.6 μm). Steady-state collisional cascade models cannot explain the increase in BD +20 307ʼs disk flux over such short timescales. A catastrophic collision between planetary-scale bodies is still the most likely origin for the system’s extreme dust; however, the cause for its recent variation requires further investigation.

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