447.01 - Multiple Large Impacts Revealed by Disk Variability in the NGC 2547-ID8 System

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Jan 10th at 9:00 AM until 10:00 AM

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Author(s): K. Su, A. Gaspar, G. Rieke, Astronomy, Steward Observatory, University of Arizona, Tucson, Arizona, UNITED STATES|A. Jackson, Centre for Planetary Sciences, University of Toronto, Toronto, Ontario, CANADA|R. Dong, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, CANADA|J. Olofsson, Instituto de Física y Astronomía, Universidad de Valparaíso, Valparaiso, British Columbia, CHILE|G. Kennedy, Department of Physics, University of Warwick, Warwick, British Columbia, UNITED KINGDOM|
Institution(s): 1. Astronomy, Steward Observatory, University of Arizona, Tucson, AZ, United States. 2. Centre for Planetary Sciences, University of Toronto, Toronto, ON, Canada. 3. Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada. 4. Instituto de Física y Astronomía, Universidad de Valparaíso, Valparaiso, Chile. 5. Department of Physics, University of Warwick, Warwick, United Kingdom.
Contributing team(s): (none)
The most dramatic phases of terrestrial planet formation are thought to be oligarchic and chaotic growth, roughly up to ages of 150 Myr, when violent collisions occur between large asteroid-size bodies of sizes up to proto-planets. Such events are marked by the production of huge amounts of debris, including clouds of dust, as has been observed in some exceptionally bright and young debris disks (termed extreme debris disks). Here we report five-year, warm Spitzer measurements from such a system around a solar-type star ID 8 in the 35 Myr-old open cluster NGC 2547. The short-term (weekly to monthly) and long-term (yearly) disk variability is consistent with the aftermaths of two large impacts involving large asteroid-size bodies. Using 3-D radiative transfer calculations, we demonstrate that an impact-produced clump of optically thick dust, under the influence of the dynamical and geometric effects, can produce short-term modulation in the disk light curves. The long-term disk flux variation is related to the collisional evolution within the impact-produced fragments once released into a circumstellar orbit. The long-term variation observed in the ID8 system is consistent with the collisional evolution of two different populations of impact-produced debris dominated by either vapor condensates or escaping boulders. The bright, variable emission by the dust produced in the aftermaths of large impacts in extreme debris disks provides a unique opportunity to study the violent events during the era of terrestrial planet formation.