Planetary Archaeology in Space and Time
Sarah Dodson-Robinson

Just as an archaeologist explores the origins of human civilization by analyzing the remains of ancient settlements, a planetary scientist may explore the origins of solar systems by investigating the remains of bygone protoplanetary disks. Here I show how my interdisciplinary research involving both numerical simulations of protoplanetary disks and spectroscopy of stars that host planets has yielded an emerging map of how, when and where planets form in the Galaxy. I begin by discussing the newly discovered mineralogical bottleneck in forming the planet species that dominates the set of known planets--the species that grows "bottom-up" from colliding planetesimals on close-in orbits. I then move to a second species of planet--that which forms via "top-down" collapse of a protostellar disk--and present evidence that newly formed such planets await discovery in the wide inner cavities that populate a subset of known protoplanetary disks. I close with a discussion of how the dominant species of forming planet may have changed during the Milky Way's history due to Galactic chemical evolution and reveal future plans for investigating changes in planet formation across cosmic time.