ERC 161 ERC 161
Glimpsing the Compositions of Sub-Neptune-Size Worlds
Sub-Neptune and super-Earth-size planets are a new category of astrophysical objects. Though absent from the Solar System, exoplanet transit, radial velocity, and microlensing surveys have revealed that they are a dominant outcome of planet formation found in abundance around other stars. The nature of these planets is not well understood. In the sub-Neptune size range a large variety of planet bulk compositions are a priori possible, including terrestrial super-Earths, mini-Neptunes with hydrogen-helium envelopes, and water-worlds with several tens of percent water by mass. In this talk, I will present recent results from my group aimed at disentangling the relative contributions from various compositional scenarios to the observed population of planets and understanding the nature and origin of these enigmatic sub-Neptune-size worlds.