ABSTRACT
The variation of a planet's obliquity plays an important role in determining its climate, and the existence of massive satellites can influence such variations. For instance, the Earth's obliquity is stabilized by the Moon, and would undergo chaotic variations without the Moon. To quantify this, I will present a simplified perturbative approach, and demonstrate that without the Moon, the stochastic change in the Earth's obliquity allows high variabilities (~40 degrees) in billion-year timescales. In addition, I will discuss spin-axis dynamics of exoplanets, with applications to compact systems as well as habitable zone planet Kepler-186f.

BIO
Gongjie Li obtained her bachelor’s degree in astrophysics from Caltech, and doctoral degree in Astronomy from Harvard. She is currently a Junior Fellow at Harvard. She will take a faculty position at Georgia Tech School of Physics, starting in Jan. 2018.