Orbital Dynamics and the Evolution of Planetary Habitability in the AU Mic System

Abstract

The diverse planetary systems that have been discovered are revealing the plethora of possible architectures, providing insights into planet formation and evolution. They also increase our understanding of system parameters that may affect planetary habitability, and how such conditions are influenced by initial conditions. The AU Mic system is unique among known planetary systems in that it is a nearby, young, multiplanet transiting system. Such a young and well-characterized system provides an opportunity for orbital dynamical and habitability studies for planets in the very early stages of their evolution. Here, we calculate the evolution of the Habitable Zone of the system through time, including the pre-main-sequence phase that the system currently resides in. We discuss the planetary atmospheric processes occurring for an Earth-mass planet during this transitional period, and provide calculations of the climate state convergence age for both volatile rich and poor initial conditions. We present results of an orbital dynamical analysis of the AU Mic system that demonstrate the rapid eccentricity evolution of the known planets, and show that terrestrial planets within the Habitable Zone of the system can retain long-term stability. Finally, we discuss follow-up observation prospects, detectability of possible Habitable Zone planets, and how the AU Mic system may be used as a template for studies of planetary habitability evolution.