Prospects for Detection of Catastrophic Collisions in Debris Disks

We investigate the prospects for detecting dust from two-body collisions during the late stages of planet formation at 1-150 AU. We develop an analytic model to describe the formation of a dusty cloud of debris and use numerical coagulation and N-body calculations to predict observable signals from these events. In a minimum mass solar nebula, collisions of 100-1000 km objects at distances of 3-5 AU or less from the parent star are observable at mid-IR wavelengths as bright clumps or rings of dust. At 24 μm, the clumps are ~0.1-1 mag brighter than emission from dust in the background debris disk. In edge-on systems, dusty clumps produce eclipses with depths of <~1.0 mag that last for ~100 orbital periods. Large-scale surveys for transits from exosolar planets, using satellites such as Kepler, can plausibly detect these eclipses and provide important constraints on the terrestrial environment for ages of <~100-300 Myr.