Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
Speaker: Meredith MacGregor, Havard University
Abstract: More than 20% of nearby main sequence stars are surrounded by debris disks, where planetesimals, larger bodies similar to asteroids and comets in our own Solar System, are ground down through collisions. The resulting dusty material is directly linked to any planets in the system, providing an important probe of the processes of planet formation and subsequent dynamical evolution. I will present highlights from ongoing work that explores how planetary systems form and evolve by (1) probing the grain properties of material in debris disks, (2) connecting debris disk structure to sculpting planets, and (3) understanding the impact of stellar flares on planetary habitability. Measurements of the long wavelength spectral index determine the grain size distribution in circumstellar disks, informing constraints on composition and collision processes. Detailed modeling of ALMA millimeter observations constrains the properties of possible planets responsible for sculpting nearby debris disk systems. Resolved imaging of debris disks also detects the host stars in many cases, yielding additional insights into the radiation environment of these planetary systems. Together these results provide an exciting foundation to investigate the evolution of planetary systems through multi-wavelength observations.