Extreme Debris Disk Variability -- Exploring the Diverse Outcomes of Large Asteroid Impacts During the Era of Terrestrial Planet Formation

Abstract

The most dramatic phases of terrestrial planet formation are thought to be oligarchic and chaotic growth, on timescales of up to 100-200 Myr, when violent impacts occur between large planetesimals of sizes up to proto-planets. Such events are marked by the production of large amounts of debris as has been observed in some exceptionally bright and young debris disks (termed extreme debris disks). Here we report five years of Spitzer measurements of such systems around two young solar-type stars: ID8 and P1121. The short-term (weekly to monthly) and long-term (yearly) disk variability is consistent with the aftermaths of large impacts involving large asteroid-size bodies. We demonstrate that an impact-produced clump of optically thick dust, under the influence of the dynamical and viewing geometry 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 time-variable behavior observed in the P1121 system is consistent with a hypervelocity impact prior to 2012 that produced vapor condensates as the dominant impact product. Two distinct short-term modulations in the ID8 system argue for two violent impacts at different times and locations. Its long-term variation 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 from the dust produced in large impacts from extreme debris disks provides a unique opportunity to study violent events during the era of terrestrial planet formation.

accepted for publication in AJ. typos and latex referencing fixed

References in corpus (15)

• The Gaia mission
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Initial Performance of the NEOWISE Reactivation Mission
• Transience of hot dust around sun-like stars
• Debris from giant impacts between planetary embryos at large orbital radii
• The History of the Solar System's Debris Disc: Observable Properties of the Kuiper Belt
• The structure of terrestrial bodies: Impact heating, corotation limits and synestias
• Large Impacts around a Solar Analog Star in the Era of Terrestrial Planet Formation
• Young Stellar Object Variability (YSOVAR): Long Timescale Variations in the Mid-Infrared
• Collisional dust avalanches in debris discs
• Variability of the Infrared Excess of Extreme Debris Disks
• Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks
• The transiting dust clumps in the evolved disk of the Sun-like UXor RZ Psc
• The first 40 million years of circumstellar disk evolution: the signature of terrestrial planet formation
• Stellar Winds and Dust Avalanches in the AU Mic Debris Disk

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