Evolution of Cometary Surfaces

Cometary surfaces are geologically active worlds shaped by complex erosional and sediment transport processes. By documenting the diverse terrains of comet 67P/Churyumov??"Gerasimenko, we show that the nucleus’s hemispherical landscape dichotomy is driven by asymmetric seasonal solar heating, which facilitates the net transport of sediment from the comet’s south to its north. Through multi-year observations, we have also witnessed these surfaces evolve in real-time, identifying dynamic changes such as the migration of ice-rich scarps and large-scale mass wasting triggered by outbursts. Recently, we have integrated thermal and sediment transport models to quantify these transport pathways across this micro-gravity environment.

By coupling our models with observations, we aim to ultimately understand how ice and dust are mixed within comets, a fundamental unknown that is intrinsically linked to how comets accreted in the protoplanetary disk and how they have been altered since. Answering this question is also critical for future sample return missions ??" the mixing of ice and dust affects not only sample handling but also how returned materials will ultimately be interpreted. In this talk, I will detail the combined observational and numerical approach we have undertaken to address these questions, and demonstrate how the exciting new field of cometary geomorphology allows us to directly link modern landscapes to our solar system’s protoplanetary disk, and even our origins.

Speaker: Sam Birch, Brown University

Room 350/372