Abstract

One of the most significant advances by NASA ’s Kepler Mission was the discovery of an abundant new population of highly irradiated planets with sizes between that of the Earth and Neptune, unlike anything found in our Solar System. Understanding these populations poses a fundamental test for models of planet formation and evolution, with important implications for habitability and the frequency of Earth-like planets. Using models of planet evolution and atmospheric evaporation, I will discuss two recent papers that shed light on the compositions and possible origins of these new populations. In particular, I will show that the most highly irradiated planets likely formed without large amounts of material from beyond the snowlike and that the period dependence of the transition between rocky and non-rocky planets can be used to constrain the origin of rocky exoplanets in general.